Noun has 1 sense

• keister(n = noun.body) arse, ass, backside, behind, bottom, bum, buns, butt, buttocks, can, derriere, fanny, fundament, hind end, hindquarters, nates, posterior, prat, rear, rear end, rump, seat, stern, tail, tail end, tooshie, tush - the fleshy part of the human body that you sit on; "are you going to sit on your fanny and do nothing?"; "he deserves a good kick in the butt"