wiktionary
ref
munchy + -s
etymonline
ref
munchies (n.)
"food or snack," 1959, plural of munchie "snack eaten to satisfy hunger" (1917), from munch (v.); sense of "craving for food after smoking marijuana" is U.S. stoner slang attested by 1971. Munch (n.) "something to eat" is attested from 1816.
