WordNet (r) 3.0 (2006):

hairdo
    n 1: the arrangement of the hair (especially a woman's hair)
         [syn: hairdo, hairstyle, hair style, coiffure,
         coif]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "hairdo":
   Afro, French knot, bangs, bob, coif, coiffure, cold wave, conk,
   cut, haircut, hairstyle, headdress, home permanent, natural,
   permanent, permanent wave, pompadour, ponytail, process, roach,
   shag, shingle, shortcut, swirl, wave