| Noun | 1. | buttocks - the fleshy part of the human body that you sit on; "he deserves a good kick in the butt"; "are you going to sit on your fanny and do nothing?"arse, ass, behind, buns, derriere, fanny, hind end, hindquarters, keister, nates, posterior, prat, rear end, tooshie, tush, seat, fundament, backside, bottom, butt, stern, rump, tail end, tail, rear, can, bum body part - any part of an organism such as an organ or extremity torso, trunk, body - the body excluding the head and neck and limbs; "they moved their arms and legs and bodies" | |