The floorboards are weakest where they 'butt' (against each other). [=where they meet, where the ends of the boards touch each other]
As a child, she was a clumsy girl who was the 'butt of' everyone's jokes. [=people made jokes about her because she was clumsy]
Why don't you 'get off your butt' and do something? [=why don't you stop being so lazy and do something?]
(..) It's weird argument, I don't like it. I didn't say anything about the stockings. But it costs me. I'm making compromises, please do the same for me. - I'm done with the butt-emptying issue. - I think I get it. It's not right. I'm done. - Enjoy your meal. - Thank you. - Pretty, huh? (..)2011 The Intouchables
(..) - We'll explain at some point. Marcelle, we have to talk... There's a problem with the training. It's not about being ready. I do not do that. I don't empty a stranger's butt. I don't even empty a friend's butt. I usually don't empty butts. It's a matter of principles. Can we talk about this later? (..)2011 The Intouchables