oaf
obit
obvi
o-dark-thirty/o’dark-thirty
off like a prom dress
old bag
old dear
old fart
old flame
old lady
old man
older than dirt
on the ball
on the g
on the piss
on the rocks
one finger salute
one night stand
oodles
oppo
out cold
out like a light
out of the blue
out the ass
out to lunch
outfit
outie
outta
oval office, the
over the hill
over the shoulder boulder holder
over-chicked
ox
oxygen thief