- off-off-Broadway
- off one's chest, get
- off one's feed
- off one's guard
- off one's head
- off one's high horse
- off one's rocker
- off-peak
- off-piste
- off plan
- off-price
- off-pricer
- offprint
- off-putting
- off-ramp
- off-reserve
- off-road
- off-roader
- off-roading
- off-sales
- offscouring
- offscourings
- offscreen
- off season
- off-season
- offset
- offset lithography
- offshoot
- offshore
- offshore dock
- offshore drilling
- offshoreman
- offshoring
- offside
- offsider
- off-site
- off someone's back
- off someone's feet
- off someone's hands
- off-speed
- offspring
- offstage
- off-street
- off stump
- offtake
- off the air
- off the beam
- off the beaten track
- off-the-board
- off-the-books
- off the cuff
- off-the-cuff
- off the deep end
- off-the-face
- off the ground
- off the handle
- off the hook
- off-the-job
- off the mark
- off-the-peg
- off the rack
- off-the-rack
- off the rails
- off the record
- off-the-record
- off the shelf
- off-the-shelf
- off the top of one's head
- off the track
- off the wagon
- off the wall
- off-the-wall
- off-topic
- offtrack
- off-trail
- off-white
- Off with her head! Off with his head!
- off year
- off-year election
- Ofgas
- Ofgem
- Of Human Bondage
- Ofili
- of it
- oflag
- of late
- OFlem
- Oflot
- OFM
- Of Mice and Men
- of necessity
- of note
- of old
- of one's life
- of one's own accord
- OFr.
- OFris
- OFS
- of service to someone, be
- of sorts
- of sound mind
- Ofsted
- oft
- OFT
- Oftel
- often
- often as not
- oftentimes
- of the devil
- of the essence
- of the first water
- of the kind
- of the moment
- Of Time and the River
- of two minds, be
- ofuro
- Ofwat
- Og
- OG
- Ogaden
- ogam
- oganesson
- Ogasawara Gunto
- Ogasawara Jima
- O gauge
- Ogbomosho
- Ogburn
- Ogden
- Ogdensburg
- ogdoad
- Ogdon
- ogee
- ogee arch
- Ogeechee
- Ogen melon
- ogham
- Ogilvie
- ogive
- Oglala
- ogle
- Oglethorpe
- Ogma
- Ogmios
- OGO
- ogonek
- Ogooué
- Ogopogo
- Ogpu
- OGPU
- O grade
- ogre
- ogress
- Ogun
- Ogygian
- oh
- Oh
- OH
- OHAC
- OHC
- OHG
- ohia lehua
- Ohio
- Ohioan
- Ohio buckeye
- Ohio River
- Öhlenschläger
- Ohlin
- ohm
- Ohm
- Ohm's law
- ohmage
- ohmic
- ohmic resistance
- ohmmeter
- OHMS
- oho
- O horizon
- Ohře
- Ohrid
- Ohrmazd
- Ohtani rule
- ohv
- oi
- Oi
- OI
- OIC
- oidium
- oik
- oil
- Oil and water don't mix
- oil beetle
- oilbird
- oil burner
- oil cake
- oilcan
- Oil City
- oilcloth
- oil color
- oil-cooled
- oilcup
- Oildale
- oil derrick
- oil drum
- oiled
- oiled silk
- oiler
- oilfield
- oil field
- oilfired
- oilfish
- oilgas
- oil gilding
- oil gland
- oil-harden
- oil hardening
- oil-immersion objective
- oillet
- oillionaire
- oilman
- oil meal
- oil of catechumens
- oil of cloves
- oil of lavender
- oil of the sick
- oil of turpentine
- oil of vitriol
- oil of wintergreen
- oil paint
- oil painting
- oil palm
- oil pan
- oilpaper
- oil patch
- oil-plant
- oil rig
- Oil Rivers
- oil sand
- oil sands
- oilseed
- oil-seed rape
- oil shale
- oilskin
- oil slick
- oil spill
- oilspot glaze
- oilstone
- oil tanker
- oiltight
- oil varnish
- oil well
- oily
- oink
- oinochoe
- ointment
- Oireachtas
- Oise
- Oistrakh
- Oita
- oiticica
- oiticica oil
- OJ
- Ojibwa
- Ojibway
- Ojibwe
- Oji-Cree
- ojo caliente
- OJT
- OK
- oka
- Oka
- Okanagan
- Okanagan Lake
- okapi
- Okavango
- okay
- Okayama
- Okazaki
- oke
- Okeechobee
- Okeechobee Waterway
- Okefenokee Swamp
- Okeghem
- Oken
- okey-doke
- Okhotsk
- Okhotsk Plate
- Okie
- Okinawa
- Okla.
- Oklahoma
- Oklahoma!
- Oklahoma City
- Oklahoma City Bombing
- okle-dokle
- Okmulgee
- okonomiyaki
- okoume
- Okovango
- okra
- Okri
