The DICT Development Group

  Anti \An"ti\ [Gr. 'anti` against. See Ante.]
     A prefix meaning against, opposite or opposed to, contrary,
     or in place of; -- used in composition in many English words.
     It is often shortened to ant-; as, antacid, antarctic.
     [1913 Webster]

  anti
      adj 1: not in favor of (an action or proposal etc.) [ant: pro]
      n 1: a person who is opposed (to an action or policy or practice
           etc.); "the antis smelled victory after a long battle"

  64 Moby Thesaurus words for "anti":
     adversary, adversative, adverse, adversive, alien, antagonistic,
     antipathetic, antithetic, antonymous, at cross-purposes, balancing,
     clashing, compensating, competitive, con, conflicting, confronting,
     contradictory, contradistinct, contrapositive, contrarious,
     contrary, contrasted, converse, counter, counterbalancing,
     counterpoised, countervailing, cross, dead against, disaccordant,
     discordant, discrepant, dissentient, enemy, eyeball to eyeball,
     fractious, hostile, inconsistent, inimical, inverse, negative,
     noncooperative, obstinate, obverse, opponent, opposed, opposing,
     opposite, oppositional, oppositive, oppugnant, overthwart,
     perverse, recalcitrant, refractory, repugnant, reverse, rival,
     squared off, uncooperative, unfavorable, unfriendly,
     unpropitious