The Collaborative International Dictionary of English v.0.48:

Groom \Groom\, v. i. [imp. & p. p. Groomed; p. pr. & vb. n.
   Grooming.]
   To tend or care for, or to curry or clean, as a, horse.
   [1913 Webster]

WordNet (r) 3.0 (2006):

groomed
    adj 1: neat and smart in appearance; well cared for; "the
           manager was a beautifully groomed young man"; "his horse
           was always groomed" [ant: ungroomed]