Used to describe a person being an
idiot / being incredibly silly and stubborn. Originating from the billy goat itself, because of its outward ridiculous appearance (big horns and a beard... You be the judge) and because of their mating habbits. Two males fighting over a female
will run at each other and butt heads to impress the female, which really, is a
stupid way to go about it.
Literally: Somebody who goes around and headbutts people.
Rodney is one crazy
fucker, who will do
anything for a laugh. Always acting the billygoat, that one.
Jane: Oww...
Tom: What's wrong? And what's with the bruise on your
forehead?
Jane: Jack. He loves acting the billygoat... Especially in bed.
Tom: Now, that was too much information.