arse (British English, offensive, slang) 1 the part of the body that you sit on; your bottom: 'Get off your arse!' = stop sitting around doing nothing ​(North American English - ass) ⭐️2 (usually following an adjective) a stupid person a smart ass (offensive, disapproving) - ​a person who thinks they are very clever and likes to show people this in an annoying way Word Origin Idioms My arse! is used by some people to show they do not believe what somebody has said. Get your arse in gear/ move your arse is a rude way of telling somebody to hurry Lick somebody’s arse ​(disapproving) means to show too much respect for somebody in authority because you want to please them. Not know your arse from your elbow means to be very stupid; to have absolutely no skill A pain in the arse is ​a person or thing that is very annoying. Work your arse off - to work very hard.