The more
popular term derived from buck naked.
some people still say buck naked, but most say
butt naked because the yanks
made a cooler version of the term.
Johnny: "Haha, I just saw your girlfriend
butt naked"
John Henry
Smith III: "You stupid American, it's "buck naked"! Bloody twit!
Johnny: "Haha, Yeah, but we are more
popular, and our term is better, so we win by default. Either way, I still saw your girlfriend naked."