* osmosis * oasis * octopus * opus * obvious * ostentatious * obsequious * oblivious * omnivorous * obsess * odious * odoriferous * odoriferous * officious * omnibus * omnivorous * onerous * ominous * optics * oppress * osteoarthritis * outguess * outclass * outdoors * overanxious * overemphasis * overzealous * overgenerous * oversuspicious * overpass * overdress * overseas * outrageous * oviparous