I think I’ll just stay home and betray myself, thanks.

Dear Word Detective:  Contemporary use of the term “double-cross” is unambiguous. I have tried to research its origins, and posted queries on other sites, with no success. “Cross” in all permutations seems not to yield an answer. Please can you tell me where we got the phrase? — Maura Emm.

Unambiguous? That’s what they want you to think. Seems pretty ambiguous to me. Not that there’s anything wrong with ambiguity, of course. Still, sometimes a little certainty would be nice. A few years ago somebody gave me a book called “You Are Being Lied To.” I started to read it, but then I began to suspect that the title might be a meta-joke and the book itself be stuffed with lies. So I parked it on the shelf and left it there, where it still sits, making me strangely queasy. Any reasonable offer will be entertained, including driving a stake through the thing.

But seriously, there does seem to be a bit of unclarity in how “double-cross,” a staple of detective fiction, “heist” movies, and “secret agent” shows on TV, is actually used in everyday speech.

The root of “double-cross” is, of course, the word “cross,” which first appeared in Old English, borrowed from the Irish “cross,” which was derived from the Latin “crux” (which also gave us “crucial,” “crusade,” “excruciate” and, of course, “crux” meaning “central or critical point”). The appearance of “cross” in Old English (replacing the existing word “rood”) was closely tied to the spread of Christianity in Europe, so it’s not surprising that its initial sense in Old English was “the instrument of crucifixion on which Jesus Christ was put to death.” Over the next few centuries, “cross” acquired a wide variety of other meanings as a verb, adjective, adverb and noun, including the “x” made in lieu of a signature by someone unable to read or write. Almost all uses of “cross” involve that “two lines crossing” meaning in some fashion, whether literally or figuratively. When we say that someone is “cross,” for instance, we mean that the person is irritably opposing or quarreling with other people, a usage which seems to be rooted in currents or winds running across (perpendicular to) a sailing ship’s course and thus impeding its progress.

One of the meanings “cross” developed as a verb, in the early 19th century, was “to cheat, to act dishonestly towards or to betray” (“It wouldn’t have happened if we hadn’t been crossed. A journalist thought he could put one over on us,” Graham Greene, 1938). This colloquial use was popularized in the lower reaches of society at that time, and often employed to describe a criminal deal “gone bad” by the betrayal of one partner by the other.

A more ornate (and dangerous) species of betrayal in this world was the “double-cross,” first appearing in print in 1834, in which the malefactor pretends to be in cahoots with not one but two other parties, each of whom is trying to cheat the other. This “man in the middle” pretends to take the side of each party in the scam until the final moment, when both crooks come up empty and the “double-crosser” walks (or runs rapidly) away with the prize.

The “double” in this “double-cross” scenario refers, of course, to the fact that such a scheme is a double betrayal, as opposed to the simple “cross” of one crook cheating another. But perhaps because this sort of scenario is hard to carry out and thus fairly rare, “double-cross” almost immediately took on the far looser meaning in common usage of simply a “cross,” i.e., “betrayal by a trusted friend.” It is sometimes said that “double-cross” in this looser sense was originally justified if the deal itself was illegal or dishonest, making the betrayal of one thief by another a case of “crossing a crosser.” If that theory were true, the term “cross” would still be used to mean a simple everyday betrayal, but such use is very rare today. Even failure to speak up for a colleague in an office meeting is likely to be labeled a “double-cross.” So I’m afraid the original complex beauty of a “double-cross” has simply fallen victim to rhetorical inflation in the Age of the Drama Queen.

All brontosauruses are thin at one end, much, much thicker in the middle, and then thin again at the far end.

Dear Word Detective: I’m trying to explain to my husband, who is not a native English speaker, what the meaning and usage of “anathema” is and why we use it without an article. Googling definitions doesn’t seem to help. It’s a great word, when needed, but I can’t explain how we use it, and why it seems to be the only noun I know that we use without an article. Can you help? This came up when he asked me to look up a film called Anatema (2006), a film in Albanian (my husband’s native language). — Peg.

I know the feeling. I used to have dreams every so often in which I’d be trying to explain, with no success, some weirdness of the English language (of which there are many) to someone. The dreams were pretty obviously based on my experiences doing live radio call-in shows, where whatever question the caller was asking was inevitably about something (a) I had written about in the recent past (good), but (b) I had completely deleted the details about from my noggin as soon as the column was done (very, very bad). To make matters worse, I had a distressing tendency to announce (a) before realizing (b), making myself sound like a total boob. To this day listening to anyone doing a radio call-in show fills me with anxiety.

“Anathema” is a strange little word, even by the inconsistent rules and standards of modern English. The first thing to remember about English, or any language, is that popular usage always trumps whatever rules we think should apply. If enough people do it for long enough, it becomes “correct,” or at least acceptable.

“Anathema” first appeared in print in English in the 16th century as an ecclesiastical term imported from the Latin “anathema,” which meant “something accursed, an evil or accursed person.” Oddly enough, the root of that Latin “anathema,” the Greek “anathema,” originally meant “something devoted to the gods” (from “ana,” up, plus “tithenai,” to place). Over time, however, the Greek “anathema” developed the negative meaning of “something or someone devoted to evil.” That meaning carried over into Latin, and then English, where today we use “anathema” to mean both someone who is literally cursed or excommunicated from a religious group or, more broadly, a thing or person greatly loathed or hated. For a fairly obscure word unchanged in form for a couple of thousand years, “anathema” remains remarkably popular today, and a search of Google News turns up more than 500 uses in the news today (“There was a time in America when such blatant hypocrisy was anathema to voters,” Boston Globe, 10/19/10?).

As that Boston Globe use illustrates, the odd thing about “anathema” is that, although it’s a noun, it is often (usually, in fact) used without the customary preceding article “an.” The Oxford English Dictionary classifies “anathema” as both a noun and a “quasi-adjective,” which neatly captures this usage. We use “anathema” as we might use a more conventional adjective such as “repulsive” or “abhorrent,” although we only use it in this way as the predicate of a verb (e.g., “Hypocrisy is anathema to voters,” not “His anathema hypocrisy angered voters”). Of course, we also use it as a normal noun with an article (“Bob’s drinking was an anathema to his boss”).

Why do we do such an odd, theoretically grammatically improper thing as using “anathema” without “an”? I can’t think of another word that is used in an exactly equivalent way, although some other nouns used as adjectives (e.g., “legion”) come close. The “an”-less use may have arisen because saying “an anathema” aloud is a bit awkward (and reminiscent of the great “Anne Elk” Monty Python sketch). It may have become popular because the literal sense of “anathema” as “accursed person or thing” has faded over time and all that’s left is an abstract noun that makes a better adjective. But whatever the original logic, we do it today because “anathema” without an article has become an accepted English idiom, and idioms are, conveniently for all of us, exempt from logic.