Generally a British Slang term for one's buttocks.
More of British Slang term, that can reference a person's rear end, specifically the buttocks. Other connotations would also refer to British Slang for a person acting like an idiot, in a derogatory sense.
Originally coined in the 1400's, and until the more modern era of the late 1800's was referencing the more physical attribute, without any real sexual or derogatory meaning attached. Originated from the 'old English' term aers, describing the tail, rump.
Most North American society uses the 'variation' of the word [Ass] for similar meanings. Example being an arsehole would be considered to be an asshole, referencing a person who is acting like a donkey.
History (Legend): Modern terminology uses variations that are more derogatory to describe homosexual males. [Arsebandit] being one such British Slang term, solely referencing male homosexuals, irrespective if they engage in anal sex.
Used to describe a person's action as being unacceptable, more idiotic, or arrogant. Primarily a British Slang term, while North American terminology would use a shorten version, ass.
It is also used in Erotic writings, to describe the buttocks.
Noteworthy: Ass was generally used to describe the animal now called the Donkey. It was believed to have come about in Victorian times, in an effort to make referencing the animal less, vulgar, thought due to the word 'ass' being more used to describe the anatomical region of a person, or their demeanor.