[late 18C+] the posterior, the buttocks, esp. as synon. with arse n. (1), as in kiss one’s backside, kick one’s backside etc.
[1990s+] (W.I.) a severe thrashing.
[1980s+] (US gay) a male homosexual who practises anal intercourse.
[1960s+] (US) nowhere, a very out-of-the-way place.
see on the bones of one’s arse under arse n.
[late 18C+] a general excl. of disdain, dismissal, arrogant contempt.