Munch \Munch\, v. t. & i. [imp. & p. p. Munched; p. pr. & vb. n. Munching.]

[Prob. akin to mumble: cf. also F. manger to eat (cf. Mange), and m[^a]cher to cher (cf. Masticate). See Mumble.]

To chew with a grinding, crunching sound, as a beast chews provender; to chew deliberately or in large mouthfuls. [Formerly written also maunch and mounch.]

I could munch your good dry oats. --Shak.

Source: Webster's Revised Unabridged Dictionary (1913)