The Collaborative International Dictionary of English v.0.48:

Perverse \Per*verse"\ (p[~e]r*v[~e]rs"), a. [L. perversus turned
   the wrong way, not right, p. p. of pervertereto turn around,
   to overturn: cf. F. pervers. See Pervert.]
   1. Turned aside; hence, specifically, turned away from the
      right; willfully erring; wicked; perverted.
      [1913 Webster]

            The only righteous in a world perverse. --Milton.
      [1913 Webster]

   2. Obstinate in the wrong; stubborn; intractable; hence,
      wayward; vexing; contrary.
      [1913 Webster]

            To so perverse a sex all grace is vain. --Dryden.
      [1913 Webster]

   Syn: Froward; untoward; wayward; stubborn; ungovernable;
        intractable; cross; petulant; vexatious.

   Usage: Perverse, Froward. One who is froward is
          capricious, and reluctant to obey. One who is perverse
          has a settled obstinacy of will, and likes or dislikes
          by the rule of contradiction to the will of others.
          [1913 Webster]

WordNet (r) 3.0 (2006):

perverse
    adj 1: marked by a disposition to oppose and contradict; "took
           perverse satisfaction in foiling her plans"
    2: resistant to guidance or discipline; "Mary Mary quite
       contrary"; "an obstinate child with a violent temper"; "a
       perverse mood"; "wayward behavior" [syn: contrary,
       obstinate, perverse, wayward]
    3: deviating from what is considered moral or right or proper or
       good; "depraved criminals"; "a perverted sense of loyalty";
       "the reprobate conduct of a gambling aristocrat" [syn:
       depraved, perverse, perverted, reprobate]

Moby Thesaurus II by Grady Ward, 1.0:

211 Moby Thesaurus words for "perverse":
   aberrant, abroad, adamant, adrift, adversary, adversative, adverse,
   adversive, alien, all abroad, all off, all wrong, amiss,
   antagonistic, anti, antipathetic, antithetic, antonymous, askew,
   astray, at cross-purposes, at fault, awkward, awry, bad-tempered,
   balancing, balky, bearish, beside the mark, bilious, bitchy,
   breakaway, bulky, cankered, cantankerous, captious, churlish,
   clashing, clumsy, compensating, competitive, con, conflicting,
   confronting, contentious, contradicting, contradictory,
   contradistinct, contrapositive, contrarious, contrary, contrasted,
   converse, corrupt, counter, counteractant, counteracting,
   counteractive, counterbalancing, counterpoised, countervailing,
   counterworking, crabbed, crabby, cranky, cross, cross-grained,
   crosswise, crotchety, crusty, cumbersome, cussed, dead against,
   deceptive, defective, degenerate, delusive, depraved, deviant,
   deviational, deviative, difficult, disaccordant, disagreeable,
   discordant, discrepant, dissentient, dissident, distorted, enemy,
   errant, erring, erroneous, excitable, eyeball to eyeball,
   fallacious, false, faultful, faulty, feisty, flawed, fractious,
   froward, grouchy, headstrong, heretical, heterodox, hostile,
   huffish, huffy, hulking, hulky, ill-tempered, illogical, illusory,
   impractical, improper, inconsistent, inconvenient, incorrect,
   inflexible, inimical, intractable, inverse, irascible, irregular,
   irritable, mean, miscreant, mulish, nefarious, negative,
   nonconformist, noncooperative, not right, not true, obdurate,
   obstinate, obstreperous, obverse, off, off the track, opponent,
   opposed, opposing, opposite, oppositional, oppositive, oppugnant,
   ornery, out, overthwart, peccant, peevish, pertinacious, perverted,
   petulant, pigheaded, ponderous, putrid, quarrelsome, reactionary,
   recalcitrant, refractory, renitent, repugnant, resistant, restive,
   reverse, revolutionary, rival, rotten, self-contradictory,
   self-willed, snappish, spiteful, spleeny, splenetic, squared off,
   stiff-necked, straying, stubborn, stuffy, sulky, sullen, surly,
   testy, touchy, ugly, unbending, uncooperative, unfactual, unfair,
   unfavorable, unfriendly, unhandy, unhealthy, unmanageable,
   unorthodox, unpropitious, unproved, unreasonable, untrue, unwieldy,
   unyielding, villainous, waspish, wayward, wide, wrong,
   wrongheaded