Green’s Dictionary of Slang

1. (Aus. teen) a general negative description, ugly, unpleasant.

1999

G. Seal Lingo 105: Other terms of current – that is, mid-1990s to late-1990s vintage – include: [...] munted, meaning deformed, ugly, unpleasant.

2. (Aus./US teen) very drunk or intoxicated by drugs.

1997–2000		College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 Munted (adj.) Totally pissed (intoxicated). Really out of it due to drinking vast amounts of alcohol.
2009		P. Temple Truth 246: Get totally munted, walk around, no fucking fear, mate, the ice fever made you fight your mate, any cunt looks at you.

3. (N.Z.) destroyed, defeated, wiped out.

2003

McGill Reed Dict. of N.Z. Sl.