[ an-tuh-nim ]
/ ˈæn tə nɪm /


a word opposite in meaning to another. Fast is an antonym of slow.Compare synonym(def 1).

Nearby words

  1. antonius,
  2. antonomasia,
  3. antony,
  4. antony and cleopatra,
  5. antony, mark,
  6. antonymous,
  7. antonyms,
  8. antre,
  9. antrectomy,
  10. antrim

Origin of antonym

First recorded in 1865–70; ant- + (syn)onym

Related formsan·ton·y·mous [an-ton-uh-muh s] /ænˈtɒn ə məs/, an·to·nym·ic, adjectivean·ton·y·my, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for antonym

  • By and by, which was once a synonym, has become an antonym of immediately, meaning at some (perhaps remote) future time.

    English Synonyms and Antonyms|James Champlin Fernald
  • In strict usage, daily is the antonym of nightly as diurnal is of nocturnal.

    English Synonyms and Antonyms|James Champlin Fernald

British Dictionary definitions for antonym


/ (ˈæntənɪm) /


a word that means the opposite of another word``empty'' is an antonym of ``full''
Derived Formsantonymous (ænˈtɒnɪməs), adjective

Word Origin for antonym

C19: from Greek antōnumia, from anti- + onoma name

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for antonym


Online Etymology Dictionary, © 2010 Douglas Harper