- oak
- oasis
- oath
- obdurate
- obedient
- obeisance
- obese
- obfuscate
- obituary
- objection
- objective
- obligation
- obligatory
- oblige
- obliging
- oblique
- obliterate
- oblivious
- obloquy
- obnoxious
- obscure
- obscurity
- obsequious
- observatory
- observatory
- obsess
- obsessed
- obsession
- obsolescent
- obsolete
- obstacle
- obstinacy
- obstinate
- obstreperous
- obstruct
- obstruction
- obstruction
- obtainable
- obtuse
- obverse
- obviate
- obvious
- occlude
- occult
- occupation
- occurrence
- octogenarian
- odds
- ode
- odious
- odium
- odometer
- odyssey
- offbeat
- offence(offense)
- offend
- offensive
- offensive
- offensive
- offhand
- onset
- officious
- offish
- offish
- off-key
- offset
- offspring
- offstage
- ogle
- ointment
- olfaction
- oligarchy
- omelet
- ominous
- omit
- omnipotent
- omnipresent
- omniscient
- onerous
- opacity
- opalescence
- opaque
- operative
- operative
- operative
- operetta
- opine
- opinionated
- opponent
- opportune
- oppose
- oppress
- opprobrious
- optimism
- optimist
- optimum
- optional
- opulent
- oracle
- oration
- oratorio
- oratory
- orchard
- orchestra
- ordain
- ordeal
- ordinance
- ordnance
- ore
- organism
- orient
- original
- originality
- ornate
- ornithology
- orthodontics
- orthodox
- oscillate
- osmosis
- osseous
- ossify
- ostensible
- ostentation
- ostracism
- ostracize
- ostrich
- other-directed
- otter
- oust
- outgoing
- outgrowth
- outlandish
- outlet
- outline
- outmaneuver
- outmoded
- outrage
- outset
- outshine
- outskirts
- outspoken
- outstrip
- outwit
- ovation
- overbearing
- overdose
- overdue
- overexposure
- overflow
- overhaul
- overlap
- overlook
- overpowering
- overreach
- override
- overriding
- overrule
- oversee
- overshadow
- overstate
- overt
- overthrow
- overture
- overturn
- overwhelm
- overwrought
- owl
- oxidize
- olfactory
- odoriferous
- oddments
- ocular
- occidental
- observance
- oblation
- obelisk
- oatmeal
- oar
- obtrude
- oligarch
- omnivorous
- onslaught
- onus
- ooze
- opiate
- optimization
- opus
- oracular
- orchid
- orifice
- orotund
- otiose
- outfox
- oversight
- overweening
- obsessive
- oleaginous
- opulence
- ornery
- oven
成人英语GRE单词单词大全〔O 〕课程包含200个英语单词词汇。