So ridiculously drunk that you feel like screaming is the only way anyone will hear you, or when your singing voice is the most beautiful thing you've ever heard, when in reality you're missing every note. Other examples include pissing in public, being promiscuous, passing out, throwing up, so on. See also inebriated, smashed, hammered, shitfaced, etc.
Did you guys see Michael the other night? He was so fuckin belligerent that he was pissing all over a Uhaul truck!
Belonging or pertaining to, the society of The Bulgarians. This may apply to actions, possessions, people, places, etc. All are within the realm of possible inclusion.
One of the Bulgarians is getting murried shortly. That is definitely belligerent, if anythingmay be considered so.