Referring to to phase "buck naked", I am almost sixty years old and have heard this phrase all my life. The word "buck" referrs to a male native american indian. The phrase "buck naked" comes from the fact that back in the early days (pre 1900) male indians would be seen riding their horses to a river or stream to bathe or do what ever, and would be totally naked on the horse. White people would see them and thus the phrase "Buck naked" was born. Coming from Oklahoma where we have many native Amercans, I believe this to be true. The use of the word "butt" is just a misunderstanding of the word "buck"