- occultism
- other man
- over-bearing
- overruling
- one's declining years
- on the bottom
- obeying
- orders
- once upon a time
- on the edge of one's seat
- obsessive about
- on the bread line
- obstructed
- offcomer
- oxidize
- on remand
- opposer
- on the job
- outlawed
- of little value
- over-critical
- on the outs
- osculation
- oblate
- old lag
- on the stocks
- overfamiliar
- overcrowd
- open to attack
- overset
- overacted
- odiousness
- on welfare
- on the barrelhead
- of substance
- overdose
- on the same wavelength
- over-wrought
- on one's last legs
- other than
- opress
- overlooked
- on pins and needles
- ovenproof
- objecting
- overplayed
- ordinances
- obsecration
- one-on-one
- old stager
- of importance
- on the doorstep
- one's cross to bear
- ordinal number
- or thereabouts
- owners
- out of humour
- offentimes
- over-brim
- on full alert
- on the qui vive
- on the blink
- on the stroke of something
- oojamaflip
- one's portion
- out-of-towner
- olde worlde
- offprint
- on the skew
- occurrences
- on the wallaby track
- offcuts
- overhadow
- overkill
- owner-occupancy
- outside of
- obligingly
- of consequence
- outer limits
- over-dramatized
- overemphasized
- of good report
- overwight
- old wives' tales
- over and above that
- out of sort
- one's salad days
- off target
- out of the ark
- on the streets
- opium
- on the dot of something
- owner-occupier
- oojamafflip
- of ample proportions
- outbalance
- oojah
- outcold
- on one's toe
- on the go