The Collaborative International Dictionary of English v.0.48:

Renitent \Re*ni"tent\ (-tent), a. [L. renitens, -entis, p. pr.
   of renit to strive or struggle against, resist; pref. re- re-
   + niti to struggle or strive: cf. F. r['e]nitent.]
   1. Resisting pressure or the effect of it; acting against
      impulse by elastic force. "[Muscles] soft and yet
      renitent." --Ray.
      [1913 Webster]

   2. Persistently opposed.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "renitent":
   antagonistic, antipathetic, apathetic, backward, balking, balky,
   breakaway, clashing, complaining, conflicting, contradicting,
   contradictory, counteractant, counteracting, counteractive,
   countervailing, counterworking, cranky, crotchety, dilatory,
   disputatious, disputing, dissentient, dissenting, dissident, firm,
   fractious, grudging, hostile, indifferent, inimical, laggard,
   loath, nonconformist, noncooperative, objecting, obstructive,
   on the barricades, opposing, oppositional, oppugnant, perfunctory,
   perverse, pokerlike, proof against, protesting, ramrodlike,
   reactionary, rebellious, recalcitrant, refractory, reluctant,
   repellent, repugnant, resistant, resisting, resistive, restive,
   retardant, retardative, revolutionary, rigid, rodlike, slow,
   slow to, starched, starchy, stiff, stiff as buckram, taut, tense,
   tight, uncooperative, unenthusiastic, unrelaxed, unsubmissive,
   unyielding, unzealous, up in arms, virgate, withstanding