contronym

noun

con·​tro·​nym ˈkän-trə-ˌnim 

variants or contranym

plural contronyms or contranyms

: a word having two meanings that contradict one another

Sometimes, just to heighten the confusion, the same word ends up with contradictory meanings. This kind of word is called a contronym. Sanction, for instance, can either signify permission to do something or a measure forbidding it to be done. Cleave can mean cut in half or stick together. A sanguine person is either hotheaded and bloodthirsty or calm and cheerful. Something that is fast is either stuck firmly or moving quickly.

—Bill Bryson, The Mother Tongue, 1990

called also antagonym, autoantonym, Janus word

Word History

First Known Use

1962, in the meaning defined above

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