Actually, I'm not sure of the meaning. Undoubtedly you know that this name's principal association is as a nickname (since boyhood) for Hank Williams, Jr.
The name was bestowed on him by his dad and taken from the name of a ventriloquist's dummy used by another performer at the Grand Ole Opry.
Some people confuse or attribute the name to Alexander the Great's horse but that was Bucephalus (Oxhead) and unrelated unless this was some kind of redneck corruption thereof. Not impossible.
Other people use the name as a first name but tend (suspiciously) to be in the music business or just wishful-thinking good ole boys. In any case, all seem to be considerably younger than Mr. Williams, who's 40+, so its use is probably derivative.
If there is any legit meaning to it, our own Mr. Lovs, an eminent Greek etymologist and Athenian eccentric, will undoubtedly share his insight with us soon.