buttocks
nates
arse
butt
backside
bum
buns
can
fundament
hindquarters
hind end
keister
posterior
prat
rear
rear end
rump
stern
seat
tail
tail end
tooshie
tush
bottom
behind
derriere
fanny
ass
the fleshy part of the human body that you sit on
he deserves a good kick in the butt
are you going to sit on your fanny and do nothing?