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shameless pleading






Flatfoot Jack and the Fuzz Brigade.

Dear Word Detective: If you were able to get to the bottom of this one you would deserve a medal! In Australia, at least, and, I think, elsewhere, the police are referred to by criminals and other elements of society as “the Jacks.” Long hours of searching and asking questions of other sites has produced exactly zero. How can this be, when the word is so consistently used across the board? Perhaps if you cannot answer my first question, you can answer my second. — Aliki Pavlou

Medal, schmedal. Just send me one of those kangaroo things and a dozen sheep. The roo can do the dishes and the sheep can mow the lawn. They would also give Brownie the Dog (who claims to be part Border Collie) something more tractable to herd than the cats she’s been working with.

“Jacks” as slang for “police” is indeed common in the UK as well as in Australia, but virtually unknown in the US, although “Jacks” may have a close relative in US slang.

jackcop08.pngTo begin at the beginning, “Jack” is what linguists call a hypocoristic (affectionate or “short”) form of the name “John,” derived from the French form of John, “Jacques.” As a slang term, “Jack” has assembled an impressive range of meanings, from “to jack up” (to increase, from the use of “jack” as a mock-personal name for a lifting mechanism) to “jack” meaning “nothing” (as in the eloquent double-negation “You don’t know jack about cars.”).

“Jack” as also been used, since at least the 16th century, as a stand-in for “the common man” or “a fellow,” as in “every man Jack needs a job.” The slang use of “Jack” specifically to mean “police officer” dates to the late 19th century (“A couple of men who were in plain clothes in the tap-room of a public-house, and were suspected by the ‘gaffer’ of being ‘Jacks’,” 1899).

This use of “Jack” to mean “police” seems to have been derived, again as a “short form,” from the use of “John” also as slang for “policeman,” and here things get interesting. This “John” was itself short for “John Darme” a joking Anglicization of “gendarme,” French for “police officer.” So “John Darme” became “John,” which became “Jack” as slang for “cop.”

But wait, it gets better. At least in Australia and New Zealand, “John Hop” was once also slang for “police” via rhyming slang, an underworld “secret language” where the phrase spoken rhymes with the hidden meaning. “John Hop,” of course, rhymes with, and signifies, “cop.” A contraction of “John Hop” (“jonnop”) is still current Australian slang for “police.”

In the US, “John” as slang for “cop” crops up only in “John Law” as the personification of the police and legal system (“We go mooching along the drag, with a sharp lamp out for John Law,” Jack London, 1906). It is possible that “John Law” harks back to the “John Darme” joke, but it may simply spring from the use of “John” in the US since the late 18th century as a personification of the average fellow (“John Q. Public,” etc.), a role now more often filled by “Joe” (as in “Joe Sixpack”).

41 comments to Jacks

  • bluejay

    My first thought on reading of the Australian term “Jacks” for police, was “Union Jack.” I’m not Australian, but I thought perhaps there was a time when those who enforced the law were either seen as (possibly resented) agents of England, or wore the British flag on their persons somewhere.

  • daughton

    I don’t speak French, but isn’t “Jacques” the French equivalent of “James” (Jacob)? Isn’t “Jean” the French equivalent of “John”?

  • RolyMole

    ‘”jacks” as slang for “police” is indeed common in the UK’ – I don’t think so!

  • Greg

    Yep, what RolyMole said. I have NEVER heard the term ‘Jacks’ used in the UK in all my 33 years, and I’ve lived all over. Piffle.

  • Chris

    Greg, I’d never heard of the term Jack being referred as police in Australia, but I don’t keep company with criminals.
    So unless you are a criminal or associate with them, how can you be sure?

  • Peter

    The popular Australian television show “Underbelly” which details the gang wars in Melbourne from 1995 to 2004 uses the term “jacks” very frequently as a replacement for police. I’m Australian and hadn’t heard this term previously, though obviously the writers who researched the organised crime syndicates must think that its common amongst these groups.

  • Tanya

    Maybe it is a regional thing…Until I moved to melbourne, Victoria (heidelberg to be exact) I had never heard the term ‘Jacks’. It is used in almost every conversation I have heard when people are referring the the Police.

    I had asked a friend to explain what it meant and she could only tell me thats what she grew up calling the police. Certainly not a new word…….I think it is probably due to location.
    Ps. I dont hang out with criminals (well none that have revealed themselves to me!! LOL!) You only have to have your ears open to hear things that might surprise you!!

  • JJ

    I was in the Victoria Police in the 90’s and pretty much all criminals referred to us as “the Jacks”. It was always used in a derogatory way and at the time I thought it to be related to use of “the Jack” to refer to a sexual disease as per the AC/DC song “The Jack”.

  • All wrong

    It is a US term. It’s because in the US they wore standard military jack boots

  • John

    The Australian Military Police, MP’s, or Provost Corps were known as the Jacks as early as WWI. Perhaps because of the slang Lance-Jack rank but I suggest the John Darme, gendarme, theory is most likely. Especially when you consider thousands and thousands of off-duty Aussie troops would have had a lot to do with the gendarmes during WWI.

  • Tomm

    i think its short for jackass

  • “Jacques” the French equivalent of “James” (Jacob)? Isn’t “Jean” the French equivalent of “John” , No i don’t think so , but would be interesting to think about it

  • In the U.S., one frequently hears the term ‘Jake’ used to refer to a police officer, especially in the speech of urban minorities. One could find a million examples in the albums of rappers from across the country. Similarly, the word ‘Johnnies’ is used by some, especially in the Midwest.

  • Clem

    Its certainly used in melbourne. I’m a criminal lawyer and all our clients use this term. I’d never heard it before. Don’t think it’s common outside crim circles!

  • Grill Gambit

    Thanks for your most informative article on the use of the term Jack to refer to coppers. It is, I can assure you, the term of choice of evildoers within this wide brown land. Coppers is #2.

    John Darme. LOL. A scream.

    And Jack as an STI is short for Jack in the Box = Pox. Jack is sometimes used to mean jack Dancer = Cancer but I prefer Spanish = Spanish Dancer. Spanish, btw is used in the car game to mean Rust. Rust = Cancer = Spanish Dancer.

    BTW Jack as Copper is popular not only with crooks but with the poor in general. West Heidelberg is a perfect place to find it in use.

  • Steve

    Police officers in Merseyside (Liverpool, England) describe the CID as “Jacks”, it’s neither derogatory (unless prefixed with fat or lazy of course) nor a compliment but simply a label. I’ve heard several explanations such as “jack of all trades” based on multi-skills, “jack the lads” based on drinking culture, and even “jumping jacks” which didn’t have an explanation. I don’t buy into any of those and find the reference in the article to plain clothes officers drinking in a pub being exposed as an interesting and likely theory. I’ve given up hope on getting to the bottom of this question and like otherEnglish references on here, it’s not common in England, it only appears to be Merseyside that uses it and it’s the officers that use the term internally, not the public (criminal or otherwise).

  • James

    Okay, so im 16 and live in the south east suburbs of Victoria, and the main terms ive heard for cops lately are ‘pigs’ and ‘the jacks’, i dont know where it originated, but its a term to put down the police really, about 2 weeks back i was at a festival in warryndyte and a fight between two girls broke out and they were really getting violent, there was a massive crowd edging them on aswell, well when the cops came people yelled ‘the jacks!’ and everyone split, my mates and all the ‘rats’ in our area refer to the cops as ‘the jacks’ so its actually a very widely known term in the south eastern suburbs of Vic from my experience most notably the Maroondah and Knox areas.

  • James

    to add to that^
    …its also a term im only starting to here more of along with stuff like ‘lad’ but it may just be stupid slang that other kids have started saying randomly

  • prawna

    I’ve been using the term since i was in primary school and I am now 40. I also come from S.E Victoria like one of the earlier posts. I originally thought it was just Australians rebellious nature and used because we didn’t want to copy the UK and use “the old bill”. After a little bit of searching and thinking the “Jackboot theory” seemed the most plausible to me imho.

  • bob

    Jacks, I learnt it in inner Melbourne as a young lad as a reference to the cops
    @Steve, jumping jacks = a nasty little ant that packs a wallop of a sting in Oz, from the same family as Bull ants. I never really thought about were that little buggers common name came from but now, perhaps there is a connection between the two.. lol

  • MrHistoricallyInaccurate

    Jack is a pretty common term here. Jack Boots doesn’t fit as the term has been used since the jacks wore standard shoes, not the GP boots some of the units wear now (particularly the Dogs and Soggies). I grew up using the term Jack to refer to Coppers (named for the copper buttons worn by the lower ranks, the Top Brass had brass buttons) and am most definitely not a criminal. At a party as s youngster we would often hear someone yell “JACKS!!!” to let anyone under 18 to hide their grog as the cops had arrived.

    @James – Lad is being used in Austrslia more and more these days, in part due to our older generations using it and in part through the popularity of UK films such as Snatch, Lock Stock, Layer Cake & others. In these films the tough guy usually greets his mates with “Orright lads?”.

    Lad never went out in London and it’s made its way back into the Aussie (esp Mrlbourne) vernacular.

  • Lady

    @ Mr historically Inccurate –
    Lad isnt bein used in the way the English use it as for young men or replacing ‘mate’ which incedentally (sic?) is more often used for people one doesnt like than ones actual mates. Lad is a term used by what is best described as Australia’s version of chavs. Lads for boys and lasses for girls. Although I believe even though there would be a similar sub culture in each state that the ‘Lads & Lasses’ are a NSW thing and may be called something else elsewhere.

  • Magpieranger

    “Jacks” comes from Cockney rhyming slang.

    Old Bill = Jack ‘n’ Jill.

  • Rod

    The name Jack for police started in the gold fields when miners who didn’t have miners licenses would call out Jack when they saw the police coming to warn others to hide so that the police wouldn’t catch them without a license.

  • Sokar

    I grew up in the Sutherland Shire, in the southern suburbs of Sydney and was a legal clerk in Sydney during the mid-late 90s (the firm represented the most well known of Sydney criminals, including all of those in Underbelly: Golden Mile, and we worked on the Wood Royal Commission. The terms “Jack” for police and “Dee” for detective were VERY common regardless of anyone’s connection, or lack thereof, with criminals.

    As much as I love the gendarme explanation, even if it is a little shaky, I am inclined to agree with the above poster that sugggested Jack & Jill. I can also see the it being used in the goldfields (but that would qualify as an early reference and not really an explanation).

  • Sean

    I had a professional Psychologist refer to the police as “The Jacks”. I didn’t know what she was talking about until I found this site. Why in the world would she use such a word? I had never heard of it until then.

  • Sean

    And she was referring to “The Jacks” in a real nasty manner. After I explained that I threw a cup into my kitchen sink and it bounced up and broke the kitchen window. She said “Wouldn’t the Jacks love to hear that”. I am not a criminal, so why would she refer to the Police as “The Jacks”. I have been going through a lot of Psychological trauma since this was said to me years ago. What is going on here, really?


    It was my impression that “Jean” was the French equivalent of “John,” and that “Jacques,” deriving as it does from the Hebrew name “Jacob,” was the French equivalent of “James.”

    Further, in the UK at least, “Jack” is not a generic term for all police, but for plainclothes detectives (viz. the novels of former Yorkshire police officer John Wainwright and the TV series JACKS AND KNAVES).

  • jean Elie

    In Ireland going to the “Jacks” means going to the toilet.

    • Ben

      I’m an expatriate living in Australia with British policing and Australian policing experience. I lived in the South of England for 30 years and had family in Liverpool. The Jack & Jill Cockney rhyming slang explanation is correct. The term may resonate through an Anglo French connection, but that is the origin. I was not aware of it only referring to plain clothes officers in UK, though it wasn’t a very common label anywhere and you’d be more likely to hear it if someone was identifying police so it may well have slight differences in meaning between regions. In Australia jack is a standard term in VIC, quite common in NSW and hardly ever heard in WA, to the point it would cause confusion. It’s mildly disrespectful everywhere but only insofar as other equivalent informal terms for police such as copper, peeler, old bill, bobby, D, demon, monarch, not offensive at all… unlike pigs or filth, which are begging for a split lip.

      The term jack is also common in British military particularly the Army and soldiering, meaning to give up, lack effort, lack heart or do nothing, i.e. jack it in, do jack, he jacked, he is jack. In this sense it is far more insulting.

  • rusty

    It is simply short for jack boots. Not a reference to the actual boots they wear today or in the past, it is used to imply that they are fascists.

  • Paul

    My grandfather, born in the NSW in 1882,told me it is simply from rhyming slang. “John Hop” means “cop” and men named John are frequently referred to as “Jack”. Hence a policeman is a “jack”. The term was frequently used in my youth.

  • Richard McGinlay

    I came here after reading ‘Cross That Palm When I Come to It’ (Sphere Books, 1974), a novelisation of a British TV show, ‘Public Eye’, by a British author, Audley Southcott. On pages 45–48 there are multiple instances of “jacks” (not capitalised) in reference to a couple of police officers (plainclothes detectives, as far as I can tell) who turn up at the hero’s office to search for stolen property. “There were two jacks outside.” “The biggest jack poked a police ID card under his nose.” “The two jacks came in,” etc. The scene takes place in Birmingham, though the hero, Frank Marker, is originally a Londoner.

  • Cheryl O'Leary

    Wow I’ll be careful what questions to ask in the future that was awesome

  • Erroneous Botch

    OK. So here’s my theory (just to add another layer). I grew up in (working class) Port Melbourne, in Victoria and was familiar with the term “The Jacks” from a very young age (so we can rule out – as a Wikipedia article I found suggested – that the term was derived in 80’s NSW, linking police to their favourite eatery; Hungry jacks (LOL):
    When I asked my father (a considerable source; trust) why the police were referred to as “Jacks”, he replied that the first “boss copper”, John Smith (yes, his real name) was appointed in NSW ( and headed a unit (The night watch) made up of ex-convicts (hence the entrenched dislike of police in Australian culture I guess). As far as I’m aware, they were indeed, as @MrHistoricallyInaccurate pointed out, named for the buttons on their coats (what’s the colour of a two cent piece? Copper; copper), but here’s where the laconic Australian wit comes in. My father stated that John Smith’s coppers were disliked not only for their backgrounds, but also their proclivity for, shall we say, unethical policing methods, with one in particular – their practice of climbing (or hopping) over people’s fences in the dark to look for possible wrong doings afoot. And this, according to my dad, is where the Australian (not cockney) rhyming slang came in. This practice earned them the nick-name “Johnny’s hoppers” or, simply, Johnny hoppers.
    Bear with me…
    Australian rhyming slang – as with it’s cockney derivative – was used as a ‘secret language’ amongst the lower SES classes (or, as @Grill Gambit would say; the poor). So for a while, if someone advised you that the Johnny hoppers were looking for you, you’d know what they meant, while most people (‘good’ people) wouldn’t.
    This would have worked well for a while, until the term’s use would have become hackneyed and therefore, counter-productive. It was at this stage, that the slang-term for coppers went from “Johnny’s hoppers” to a simple abbreviation for John (Smith): Jack.
    So that’s my two bob’s worth: Ultimately, the term Jack was derived the same way the English term, Bobby (from Robert Peel), was. It was an abbreviation of the fella’s name that was running them.
    Yes, it’s (mostly) anecdotal, but it’s always seemed to make sense to me.

  • Jon

    The term appears on p19 of the play ‘Love In A Veil’ (1719) by Richard Savage. “The Governour with a whole trooop of Jacks… come to seize you”. It predates the gold rushes.

  • Jo

    I know being from Liverpool that lots of Scousers/prisoners were resettled in Australia in its earliest settlements. There were more scouse migrants in 50’s and 60’s on the £10 boats. Maybe if it was formerly used in Liverpool, that is how it migrated to common use in Australia and NZ

  • Charmaine Clancy

    I’ve been looking for a slang term for police, used by the public, the police (casually) and criminals during the 1940s in Melbourne. Sounds like jacks (not sure if it would be capitalised or not!) could be one, have had wallopers suggested as well? I find lots of sites with terminology, but it’s hard to find the popularity during different eras.

  • John Dahmer

    Well… I AM a criminal in NSW and we DO refer to police, but only plainclothes, as Jacks. Often.

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