An odd word, one that seems not to be in use much outside of Hamilton.
A munter is anyone who is loud, obnoxious, quite probably drunk, probably into rugby (you tend to be a Rugby Munter if you play/watch the game and a Rugby Geek only if you referree it and/or write the rules).
GreigMcGill: I disagree. Munters need not be loud or obnoxious. They are simply the (and this sounds snobby) "low brow" people with bland taste in many things. A typical Munter cares only for Ford or Holden, listens to The Rock or Hauraki, drinks Lion Red or Waikato, and enjoys reality television.
Alcohol makes normal people into munters.
Munting can be a lot of fun.