- overload oneself
- on the fritz
- of no fixed address
- off Broadway
- out of love
- oil the wheels of
- on the mend
- over the fence
- overman
- out of true
- outer limit
- on one's toe
- one's better half
- once-over
- of distinction
- outspokenness
- overfamili-arity
- outbalance
- of ample proportions
- on the streets
- outcold
- owner-occupier
- opium
- oojah
- oojamafflip
- oldsters
- out of hand
- outperform
- over-effusive
- oddness
- otiose
- offcut
- overlooking
- one-horse
- on one's lonesome
- one' cards
- on the understanding that
- of little account
- osteopathy
- outer reaches
- out-standing
- on this account
- of the highest quality superlative
- object of the exercise
- orthoepy
- on one's beam-ends
- oppo
- one's dole
- other half
- oomph
- outrival
- opinions
- on that account
- on the money. exclamation precisely
- of moment
- on the ark
- offsider
- osculate
- oil someone's palm
- outspokenly
- of no account
- on one's Jack Jones
- omitting
- opaline
- oxbow
- on the fence
- overstep
- overseeing
- on the bread-line
- overhasty
- out of control
- omnium gatherum
- overpitch
- orotund. bombastic
- out of one's depth
- on the subject of
- openhandedness
- over the hill
- overlong
- okay
- on one's Pat Malone
- one in a million
- on hold
- one-off
- on us
- overexcited
- on the mark
- on cloud seven
- on the top of the world
- outstandingly
- on the breadline
- one-liners
- out of whack
- ombudsman
- oldster
- old womanish
- on the rampage
- outflowing
- over-adventurous
- oik