- overprint
- oversell
- oology
- okra
- omni competent
- out of one's own head
- out for the count
- on the whole, all in all
- otherwise engaged
- over the top immoderate
- on the surface
- on the sly secretly
- on the horns of a dilemma
- on the run at
- on the rocks
- on purpose
- on one's own solitary
- overflow
- outwit
- outrun
- oscillate
- orthodoxy
- orgiastic
- organic
- opt
- oppose
- out of fashion
- obelus
- occupy
- occasional
- obloquy
- on the level
- on the house
- on a high
- oppugn
- on the trot
- off-time
- oxonian
- overbid
- oceania
- outside work
- oncologist
- off the beat
- outgun
- orbital
- off the rails
- out of
- one million
- otiosity
- off spring's
- olive yard
- of his ilk
- opeidoscope
- offensively inquisitive query
- one who has controlled passions
- obscurantism
- opaqueness
- oh for
- oppugnancy
- overreach oneself
- open face
- ownership certificate
- old age home
- out of range
- op
- oxails
- out bargain
- open field
- open
- obfuscate
- opportunity
- oops-a-daisy
- objective
- oocyte
- obliging
- obliterate
- onyx
- oenophile
- onslaught
- one who reprimands
- onerousness
- off the point
- offence
- offer
- office
- officer
- overshadow
- overlay
- one who intimates
- old head on young shoulders
- old school
- one who ignores household duties as laid down by the scriptyres
- old-time
- one who gives joy
- overjoyed
- on firm or solid ground
- one who erects
- one who collects customs-tax
- one who acts
- on the rove