Definition of anti- in US English:

anti-

(also ant-)

prefix

  • 1Opposed to; against.

    ‘antiaircraft’
    1. 1.1 Preventing or suppressing.
      ‘antibacterial’
    2. 1.2 Reversing or undoing.
      ‘anticoagulant’
      ‘antigravity’
      ‘antipruritic’
    3. 1.3 The opposite of.
      ‘anticlimax’
      dissenting, dissident, disagreeing, differing, discordant, contradicting, contrary, negative, anti-
      View synonyms
    4. 1.4Physics The opposite state of matter or of a specified particle.
      ‘antimatter’
      ‘antiproton’
    5. 1.5 Acting as a rival.
      ‘antipope’
    6. 1.6 Unlike the conventional form.
      ‘antihero’

Origin

From Greek anti ‘against’.

Pronunciation