The Collaborative International Dictionary of English v.0.48:

grouchy \grouch"y\ (grouch"[y^]), adj.
   given to complaining or grumbling; prone to show annoyance at
   slight provocation; irritable.

   Syn: crabbed, crabby, cross, fussy, fussbudgety, grumpy,
        bad-tempered, ill-tempered.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

grouchy
    adj 1: annoyed and irritable [syn: crabbed, crabby, cross,
           fussy, grouchy, grumpy, bad-tempered, ill-
           tempered]