From WordNet (r) 3.0 (2006):
cinch
n 1: any undertaking that is easy to do; "marketing this product
will be no picnic" [syn: cinch, breeze, picnic,
snap, duck soup, child's play, pushover,
walkover, piece of cake]
2: stable gear consisting of a band around a horse's belly that
holds the saddle in place [syn: cinch, girth]
3: a form of all fours in which the players bid for the
privilege of naming trumps
v 1: tie a cinch around; "cinch horses" [syn: cinch, girth]
2: make sure of
3: get a grip on; get mastery of