An exaggerated way to say the already chock-full-of-attitude "obviously". Also, used with more masculinity and aggressiveness. Stems from both California and New Jersey, where men with too much testosterone would mix up their words while trying to talk like valley girls.
Dennis: Hey, check out the lady lumps over there!
James: What, on that old statue?
Dennis: Boviously.
James: What, on that old statue?
Dennis: Boviously.
by JamesInTheFlesh June 13, 2010