WordNet (r) 3.0 (2006):

sex appeal
    n 1: attractiveness to the opposite sex [syn: sex appeal,
         desirability, desirableness, oomph]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "sex appeal":
   agacerie, allure, allurement, appeal, attraction, attractiveness,
   beguilement, beguiling, bewitchery, bewitchment, blandishment,
   cajolery, captivation, charisma, charm, charmingness, come-hither,
   enchantment, enthrallment, enticement, entrapment, fascination,
   flirtation, forbidden fruit, glamour, inducement, interest,
   inveiglement, invitation, magnetism, seducement, seduction,
   seductiveness, sexual attraction, snaring, tantalization,
   temptation, winning ways, winsomeness, witchery, wooing