A contronym, sometimes spelled contranym (occasionally antagonym or autoantonym), is a word with a homonym which is also an antonym. For example, the word "fast" can mean "moving quickly" as in "running fast", or it can mean "not moving" as in "stuck fast".

Some pairs of contronyms are true homonyms, i.e. distinct words with different etymology which happen to have the same form. For instance cleave "separate" is from Old English clēofen, while cleave "adhere" is from Old English cleofian, which was pronounced differently. Other examples include let — "hinder" (as in tennis) or "allow".

Other contranyms result from polysemy, where a single word acquires different, and ultimately opposite, senses. For instance quite, which meant "clear" or "free" in Middle English, can mean "slightly" (quite nice) or "completely" (quite beautiful). Other examples include sanction — "permit" or "penalize"; bolt (originally from crossbows) — "leave quickly" or "fixed"; fast — "moving rapidly" or "unmoving". Many English examples result from nouns being verbalized into distinct senses "add <noun> to" and "remove <noun> from"; e.g dust, seed, stone.

Often, one sense is more obscure or archaic, increasing the danger of misinterpretation when it does occur; for instance, the King James Bible often uses "let" in the sense of "forbid". An apocryphal story relates how an English monarch described St Paul's Cathedral as "awful, artificial and amusing", meaning "awesome, clever and thought-provoking".

See also

• -onym
• antonym

External link:

• Antagonyms
• List of autoantonyms