Meaning

noun periodic shedding of the cuticle in arthropods or the outer skin in reptiles

verb cast off hair, skin, horn, or feathers

originFrom Middle English mouten, from Old English *mutian (cf. bemutian), from Latin mūtō, mūtāre. Doublet of mute and mutate. Un-etymological ⟨l⟩ was introduced into the spelling by mistakenly assuming a French origin with -l- (compare fault, vault and solder with correctly restored etymological ⟨l⟩).

Etymology from Wiktionary, CC BY-SA 3.0