Idioms beginning with O. Select an idiom for more details.

(something) occurs to you

If something occurs to you, you think of it.

a one-track mind

If someone has a one-track mind, they spend most of their time thinking about one subject.

off the cuff

If you speak off the cuff, you speak without planning what you will say beforehand.

off the record

If you say something "off the record", you don't want it in the public record, or reported in the media.

off the top of your head INFORMAL

If you give someone information off the top of your head, you do so from memory, without checking beforehand.

off your own bat British English

If you do something off your own bat, you do it without being asked to or told to.

old hat

If something is old hat, it's old-fashioned and no longer seen as being modern and new.

on the back burner

If a plan or a project is on the back burner, it isn't being worked on at present, but it might be completed in the future.

on the ball INFORMAL

If you're on the ball, you're alert and you know what's going on around you.

on the off-chance

You can say you're doing something "on the off-chance" if you're doing it because it might lead to something that you want, even though it's not definite.

on the one hand | on the other hand

You can say "on the one hand" before describing one of two contrasting ideas, options, or opinions, and then say "on the other hand" before describing the other one.

on the record

If you say something "on the record", you say it on the understanding that it will be part of the public record, and can be reported in the media.

on the strength of

If you do something on the strength of certain advice or information, you do it because the advice or information suggests doing it.

on your last legs | on its last legs INFORMAL

If you say you're on your last legs, it can mean you're close to exhaustion, or it can mean you're close to death. If a thing is on its last legs, it's close to breaking or wearing out.

once and for all

If you do something once and for all, you do it in a way that's final and it means you'll never have to do it again.

once in a blue moon

If something happens once in a blue moon, it happens very rarely.

one in a million

If you say someone is "one in a million", you mean they're an exceptionally good person.

out of the blue

If something happens out of the blue, you're not expecting it to happen and you're surprised when it does.

out of the question

If something is out of the question, it cannot be considered because it's impossible or it's not allowed.

out of your depth

If you're out of your depth, you're in a situation that you don't have the experience to handle, or the knowledge to understand.

out-of-date (1)

Something is out-of-date if it is old and therefore no longer useful or no longer accurate.

out-of-date (2)

If something like a passport or a credit card is out-of-date, it cannot be used anymore because the period during which it was valid is over.

over the moon INFORMAL

If you're over the moon about something, you're extremely happy and excited about it.

over the top

You can say something is over the top if you think it's too extreme or it's more than a situation needs or deserves.

over your head

If something you hear or read is over your head, or goes over your head, you don't understand it because the language or the ideas are too advanced for you.

Contributor: Matt Errey