Green’s Dictionary of Slang

munch n.

[abbr. munchie n.1 ]

(orig. US teen) a snack.

[US] W. Safire What’s the Good Word? 304: ‘Dinner’ is a ‘major munch’.
Spud ‘Marijuana’ page on Spud’s Page [Internet] That’s about it for now, I don’t know about you but I fancy a munch!