From WordNet (r) 3.0 (2006):
gripe
n 1: informal terms for objecting; "I have a gripe about the
service here" [syn: gripe, kick, beef, bitch,
squawk]
v 1: complain; "What was he hollering about?" [syn: gripe,
bitch, grouse, crab, beef, squawk, bellyache,
holler]
