The Collaborative International Dictionary of English v.0.48:

Gracile \Grac"ile\, Gracillent \Grac"il*lent\a. [L. gracilis,
   gracilentus.]
   Slender; thin. [Obs.] --Bailey.

   Syn: willowy.
        [1913 Webster]

WordNet (r) 3.0 (2006):

gracile
    adj 1: slender and graceful [syn: gracile, willowy]

Moby Thesaurus II by Grady Ward, 1.0:

102 Moby Thesaurus words for "gracile":
   Attic, Ciceronian, aesthetic, aesthetically appealing, airy,
   attenuate, attenuated, attractive, beauteous, beautiful, boyish,
   chaste, civilized, classic, clear, cultivated, cultured, dainty,
   delicate, diaphanous, diluted, direct, discriminating, easy,
   elegant, endowed with beauty, ethereal, exquisite, eye-filling,
   fastidious, fine, fine-drawn, finespun, finished, flimsy,
   flowerlike, frail, gauzy, girlish, gossamer, graceful, gracious,
   handsome, heavy, insubstantial, lacy, light, limpid, lovely, lucid,
   misty, natural, neat, nice, papery, pellucid, perspicuous, plain,
   polished, pretty, pulchritudinous, pure, rare, rarefied, refined,
   restrained, round, simple, slender, slenderish, slight,
   slight-made, slim, slimmish, slinky, small, sophisticated,
   straightforward, subtle, svelte, sylphlike, tasteful, tenuous,
   terse, thin, thin-bodied, thin-set, thin-spun, thinnish,
   threadlike, trim, unaffected, unlabored, vague, wasp-waisted,
   watered, watered-down, watery, weak, willowy, wiredrawn, wispy