From WordNet (r) 2.0 (August 2003) [wn]:
chopper
n 1: a grounder that bounces high in the air [syn: chop]
2: informal terms for a human `tooth' [syn: pearly]
3: an aircraft without wings that obtains its lift from the
rotation of overhead blades [syn: helicopter,
whirlybird, eggbeater]
4: a butcher's knife having a large square blade [syn:
cleaver, meat cleaver]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Chopper \Chop"per\, n.
One who, or that which, chops.
[1913 Webster]