The Collaborative International Dictionary of English v.0.48:

Recalcitrant \Re*cal"ci*trant\ (r[-e]*k[a^]l"s[i^]*trant), a.
   [L. recalcitrans, p. pr. of recalcitrare to kick back; pref.
   re- re- + calcitrare to kick, fr. calx heel. Cf.
   Inculcate.]
   Kicking back; recalcitrating; hence, showing repugnance or
   opposition; refractory.
   [1913 Webster]

WordNet (r) 3.0 (2006):

recalcitrant
    adj 1: stubbornly resistant to authority or control; "a
           fractious animal that would not submit to the harness";
           "a refractory child" [syn: fractious, refractory,
           recalcitrant]
    2: marked by stubborn resistance to authority; "the University
       suspended the most recalcitrant demonstrators"

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "recalcitrant":
   adamant, adversary, adversative, adverse, alien, antagonistic,
   anti, antipathetic, antithetic, at odds, averse, beyond control,
   bouncing, bounding, breachy, breakaway, clashing, competitive,
   complaining, con, conflicting, contradicting, contradictory,
   contrary, contumacious, counter, counteractant, counteracting,
   counteractive, countervailing, counterworking, cranky, cross,
   crotchety, cursory, defiant, deviant, differing, disaccordant,
   disagreeing, disinclined, disobedient, disputatious, disputing,
   dissentient, dissenting, dissident, enemy, firm, forced, fractious,
   headstrong, hostile, immovable, impatient of control, incorrigible,
   indisposed, indocile, indomitable, inflexible, inimical,
   insubordinate, insuppressible, intractable, involuntary,
   irrepressible, mutinous, negative, nonconformable, nonconforming,
   nonconformist, noncooperative, nonobservant, objecting, obstinate,
   obstreperous, obstructive, on the barricades, opponent, opposed,
   opposing, opposite, oppositional, oppositive, oppugnant, ornery,
   out of hand, overthwart, perfunctory, perverse, proof against,
   protesting, reactionary, reactionist, rebellious, rebounding,
   recoiling, recusant, refractory, reluctant, renitent, repellent,
   repercussive, repugnant, resilient, resistant, resisting,
   resistive, restive, retardant, retardative, revolutionary, rival,
   shrewish, springing, stiff, stubborn, sulky, sullen, unadaptable,
   unadjustable, unbending, unbiddable, uncompliant, unconforming,
   unconsenting, uncontrollable, uncooperative, undisciplined,
   unfavorable, unfriendly, ungovernable, unmalleable, unmanageable,
   unmoldable, unpropitious, unruly, unsubmissive, untoward,
   unwilling, unyielding, up in arms, wayward, wild, withstanding