“Antagonyms” is probably my favourite term for them, but nobody seems to use it much. So let’s call them “contranyms”. Although you might want to spell it “contronyms”: my copy of Collins is silent on the subject, so the spelling is to choice.
What are they? They are homophones that have opposing definitions: in other words, the same word bearing two contradictory meanings. They’re quite the curio for head-in-a-book 10-year-olds, and also Exhibit A in the prosecution’s case that language is an organically grown, fecund and uncontrolled thing, not a carefully organised and controlled system. And a list of them – whether assembled to prove a linguistics point or bamboozle a junior reader – does seem to prove that conclusively.
Except that some of the entries on the lists can be a little disappointing. Take “sanction”, for example. As a noun, it’s cited ubiquitously as a contranym, but the true opposite of “permission”, its first meaning, would actually be “prohibition” – not “punishment”, which is the word’s other meaning. One’s broadly approbatory, the other broadly disapprobatory – one’s good and one’s bad – but that seems a disappointingly vague standard to qualify as a true contranym.* A penalty isn’t quite the opposite of a permit: it’s the thing that comes after the breach of a prohibition, not the prohibition itself. The opposed definitions don’t provide the kind of precision required, say, for one of those “Black is to White as Over is to _____” questions you get in intelligence tests.
And picking on Wikipedia is cheap sport, of course, but its list of auto-antonyms (as it prefers to call them) contain numerous examples that don’t come remotely close to being opposites:
“Discursive” can mean “covering a wide field of subjects; rambling” or “proceeding to a conclusion through reason rather than intuition”.
“Snuff” can mean a specific kind of tobacco, as well as to inhale it, and to extinguish.
I’m beginning to wonder if there are fewer authentic contranyms than is sometimes supposed. Certainly none of the above will quite do – not when there are several words (also in Wikipedia’s list) that are much better candidates for the description, such as “to dust”, which can mean either to remove dust from a surface or to scatter it thereon, as from a flour dredger.
Or – of course – “literally”, which, as we know, has come to mean both “without exaggeration” and “with exaggeration”. It’s fast becoming one of the most authentic – that is to say paradoxical – contranyms there is. At least, it is at the moment: but as we were discussing last week, maybe its days as a true contranym are numbered, and a new life – as just another single-meaning, ho-hum intensifier – is just around the corner.
*Unless “contranym” is itself a contranym, meaning both “words that mean the opposite” and “words that do not mean the opposite”.