A word with several meanings is polysemous. One of the more interesting forms is the Janus word, also sometimes called an autoantonym or a contranym, in which two of the meanings of the word are opposites of each other. A Janus word is so named for Janus, a Roman god that is identified with doors, gates, and all beginnings and that is depicted with two opposite faces.
Examples of Janus words are:
- CLEAVE to divide by or as if by a cutting blow or to adhere firmly
- DUST to make free of dust or to sprinkle with fine particles
- OVERLOOK to look past, to miss or to look over: INSPECT
- ROCK something like a rock in firmness or a swaying or tilting movement
- SANCTION to give effective or authoritative approval or consent to or coercive measure intended to discourage
- SCREEN to conceal from view or to display (e.g., screen a film)
- TRIP dance, skip or caper with light quick steps or to stumble
- OVERSIGHT watchful and responsible care or an inadvertent omission or error
- FAST firmly fixed or moving or able to move rapidly
These opposite meanings often occur because the word is, in fact, derived from quite different words. Cleave is an example of this: Cleave (verb) is descended from Middle English cleven, from Old English cleofan; akin to Old Norse kljufa meaning to split, Latin glubere meaning to peel, and Greek glyphein meaning to carve. On the other hand, cleave as an intransitive verb is descended from Middle English clevien, from Old English clifian, akin to Old High German kleben meaning to stick. Thus you have two very different sources for what appears today as a single word, resulting in a word that is its own antonym.
Luckily it's difficult to create a sentence using a Janus word that is truly ambiguous. Context will generally tip off the reader or listener to the intended meaning.
See if you can come up with an ambiguous sentence using one of the examples above. Can you think of any other Janus words? Post your replies!
Sources: Merriam-Webster's Eleventh Collegiate Dictionary and the Internet; logo from Janus Capital Group.