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]