out of the question out of use out of touch with out of the way out of tune with out of sight out of the ordinary out of the blue out of stock out of step out of sorts out of season ox owner own up own owing to owing owe oxygen overtake overlook overall overcome overhead overcoat overseas overnight over the hill over and over again over and above oven oval outward outstanding over outside output outlook outline outer outlet outdoor out of work orange orbit oral or something outset or else or so outcome or optional option optimistic opponent opposite oppose opportunity opinion operator operational operation out of print out of practice out of pocket out of place out of order out of luck out of line out of joint out of control out of hand out of doors out of date out of breath out of action out of ours out ourselves our ounce ought to out of character otherwise other original other than origin organization organise organism organ organic ore organisation operate opera open up ordinary only too orderly open onto order orchestra one day opening only onion oneself one way or another one another on the part of on the point of on the other hand on the one hand one by one on the job on the move on the road to on the increase on the hour on the horizon on the house on the average on the go on the button on the air on the alert on the grounds of on that score on the quiet on schedule on occasion one after another on the contrary on sale on record on purpose on paper on order once upon a time once in a while once more once and for all once on top of on top on time on thin ice on the whole on the trot on the table on the strength of on the spur of the moment on the spot on the side on the shelf omit old okay on the run oil official often officer office offend offensive offer offense offence off the record off the hook off the air off duty off balance off of sorts of note of necessity of late of course odds and ends of a kind of odd October of no account ocean occurrence occur occupy occupation occasional occasion obvious obtain obstacle on no account observer observe observation oblige obligation objective on loan on line on foot on fire on edge on duty on file on end on earth on demand on business on board on condition that on behalf of on and on on account of object on cue obey on a diet on on a scale