The Collaborative International Dictionary of English v.0.48:

D'ebutant \D['e]`bu`tant"\, n.; fem. D'ebutante
\D['e]`bu`tante"\ [F., p. pr. of d['e]buter to have the first
   throw, to make one's d['e]but. See D['e]but.]
   A person who makes his (or her) first appearance before the
   public.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "debutant":
   abecedarian, alphabetarian, apprentice, articled clerk, baby,
   beginner, boot, catechumen, deb, entrant, fledgling, freshman,
   greenhorn, greeny, ignoramus, inductee, infant, initiate, learner,
   neophyte, nestling, new boy, newcomer, novice, novitiate,
   postulant, probationer, probationist, raw recruit, recruit, rookie,
   tenderfoot, trainee, tyro