WordNet (r) 3.0 (2006):

sexy
    adj 1: marked by or tending to arouse sexual desire or interest;
           "feeling sexy"; "sexy clothes"; "sexy poses"; "a sexy
           book"; "sexy jokes" [ant: unsexy]
    2: exciting sexual desire [syn: aphrodisiac, aphrodisiacal,
       sexy] [ant: anaphrodisiac]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "sexy":
   alluring, amorous, animal, aphrodisiomaniacal, appealing, arousing,
   bawdy, bedroom, blue, broad, captivating, carnal, clitoromaniacal,
   coarse, come-hither, concupiscent, dirty, ejaculatory, enchanting,
   erogenic, erogenous, erotic, eroticomaniacal, erotogenic,
   erotomaniacal, exciting, explicit, fascinating, filthy, fleshly,
   flirtatious, foul, gamic, goatish, gross, gynecomaniacal,
   heterosexual, horny, hot, hot-blooded, hysteromaniacal, immodest,
   improper, indecent, indecorous, indelicate, inviting, itching,
   ithyphallic, lascivious, lecherous, lewd, libidinal, libidinous,
   lickerish, lubricious, lustful, lusty, naughty, nuptial,
   nymphomaniacal, obscene, off color, off-color, orgasmic, orgastic,
   oversexed, passionate, pornographic, potent, priapic, procreative,
   provocative, prurient, purple, racy, randy, raunchy, ribald,
   risque, rough, rude, salacious, salty, satyric, seductive, sensual,
   sensuous, sex, sex-starved, sexed, sexlike, sexual, shady,
   shameless, smutty, spicy, steamy, straight, striking, stunning,
   suggestive, tempting, titillating, undersexed, unsatisfied,
   unseemly, venereal, voluptuous, vulgar