- out of service
- on a par witih
- overwhelm
- on the streets homeless
- overthrow
- on time punctually
- omnipresence
- overcrowded
- ominous
- on the gui vive
- outside verandha
- one-way
- oxygen tent
- of
- overnight
- on terms of
- oil-colours
- oracy
- omninescience
- ocherous
- outsourcing
- outstation
- oral presentation
- oblige someone with
- oceanography
- olio
- old testament
- onanism
- on the first instance
- over hastiness
- one-twelfth
- old top
- offal pit
- other-directed
- on the ropes
- on one mettle
- owe person a grudge
- on stilts
- olericulture
- on the record
- outboard
- orientated
- ohm
- old bachelor
- out wardens
- open and above board
- on its merits
- ooze from
- oversleep
- on parole
- optical scanner
- out bar
- oast
- organic chemistry
- ordinary run of men
- onam
- own brand
- ones right hand
- over head and ears
- outrank
- one with deformed limbs of without limbs
- old saying
- oaten
- ostracise
- oviparous
- oedipus
- otherness
- ogling
- oversimplify
- on board
- over the counter
- one man
- orgies
- outward things
- overexposure
- ocr
- ontology
- ochery
- oil squeezers
- one who dedicates
- onliness
- oozing latex
- onto
- opposite bank
- overpay
- overexertion
- ominiscience
- owe to
- ostensibility
- office bearer
- one-way street
- offense
- oncology
- on one's high horse
- over toned
- orpiment
- of price
- on the stroke
- orbiculation
- octopod