- outlet
- outright
- over and above
- outfielder
- outfield
- outer door
- outer cover
- on the streets homeless
- outdoor scenes
- outcome
- outside verandha
- one-way
- oracy
- oceanography
- old testament
- on the record
- occlussion
- optical scanner
- overstaff
- obeisant
- one who feeds
- otherness
- orgies
- off-wind
- overexertion
- ostensibility
- office bearer
- octavo
- objectiveness
- over toned
- overdevelop
- optometry
- ornithology
- old money
- overexcite
- object library
- obligate
- obliged
- obliquely
- obscene
- obscurantist
- obscuration
- odorous
- out of pocket
- of no effect
- off-road
- offbeat
- out of one's mind
- offensive
- old stage
- old woman
- out of nowhere
- oleander
- on credit
- out cold
- on fall
- on occasion
- on one's hand
- on one's legs
- on the nose
- on the one hand
- oscillatory
- on the part of done by
- os
- oryx
- orthographic
- one who eats
- one who is inactive
- one who is not done his duties
- one who reads
- one who sleeps at sunrise
- one who throws
- onewho repeats what another says
- onion-skin
- onlooker
- only
- onomatoepic
- onomatopoeic
- onus
- onymous
- oogenesis
- oophorectomy
- ornate
- openly
- operational
- ophthalmic
- ophthalmologist
- opine
- opinionative
- originate
- opium-den
- originally
- ordinary fly
- ordinary man
- ordnance
- orectic
- oregano
- organiser
- oriental
- original