The Collaborative International Dictionary of English v.0.48:

Resilient \Re*sil"i*ent\ (-ent), a. [L. resiliens, p. pr.]
   Leaping back; rebounding; recoiling.
   [1913 Webster]

WordNet (r) 3.0 (2006):

resilient
    adj 1: recovering readily from adversity, depression, or the
           like
    2: elastic; rebounds readily; "clean bouncy hair"; "a lively
       tennis ball"; "as resilient as seasoned hickory"; "springy
       turf" [syn: bouncy, live, lively, resilient,
       springy]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "resilient":
   able to adapt, adaptable, adaptive, adjustable, airy, alterable,
   alterative, bouncing, bouncy, bounding, breezy, buoyant, carefree,
   changeable, checkered, convalescent, corky, debonair, effervescent,
   elastic, ever-changing, expansive, extensile, flexible, flexile,
   fluid, free and easy, impermanent, jaunty, kaleidoscopic, light,
   lighthearted, lightsome, lively, malleable, many-sided,
   metamorphic, mobile, modifiable, movable, mutable, nonuniform,
   perky, permutable, plastic, protean, proteiform, rebounding,
   recalcitrant, recoiling, recuperative, recuperatory, repercussive,
   responsive, reviviscent, rubbery, springing, springy, stretch,
   stretchable, stretchy, supple, transient, transitory, variable,
   volatile, whippy