butt is acceptable in our house, yes. However, things slightly worse in nature like damn and hell are not. It's not some horrible, unforgiveable offence, but it's not ok with either dh or I. We're not proper by any means but, cussing is a definate no around here. I guess I've just never seen "butt" as a cuss word. Booty is used equally with the word butt around our house as well.
I remember the first time someone clued me in to the fact that not everyone is comfortbale with that word. In the 6th grade I was spending the night at my friend Amy's house for the first time. I said butt in the middle of a sentence (to indicate something to do with someone's backside) and both my friend and her mom spun their heads around like I'd just admitted to murder! My friend stood in the background with buggy eyes, shaking her head as if to say, "if you valve your life don't say that around my mom." and her mother gave me the dirtiest look I think I've ever gotten. I had NO IDEA what I had done or said to make her so upset. She said, "excuse me?" and I just stood there saying, "uhhhhhhh..." until my friend saved me by saying, "we say bottom." I still had no idea what was going on until her mom told me that young ladies do not say the word "butt".
I'm still friends with Amy today and get along great with her mom as well. However, even as a 25 year old, mature, adult, I still know not to say "butt" in front of her mother if I don't want a lecture and to be corrected for my language.