One (or more) males in a group who always think they are funny, but instead embarrass their friends - especially around women.
Tom: "Ugh, I was talking to these two hot chicks, and then Doug comes up outta nowhere and starts dry humping me, thinking he was being funny"
Dave: "What a butt clown...I've got his car keys, let's just take off and leave him here"
someone who likes to check out the anus of homeless people in central park, also used to desrcibe a koala in the outback. if you have only one left nut and two right ones you are probably a victim of child abuse and see a psycologist. thats all for now if you want to know more you are a loser and should get a life before the devil steels your soul and you get blown up by a suicide bombing.
damn that guy who looked in that hobo's asshole is a BUTTCLOWN
damn that koala that i saw on animal planet is a buttclown
damn that guy who flashed us with 3 balls should see a doctor
A person who dresses up their butt like a clown, and acts like a fool. The person paints his butt like a clown, and puts a big red nose in the hole.
He's a buttclown man.