moult

Origin

From Middle English mouten, from Old English *mutian (attested in bemutian, “to exchange for”), from Latin mūtō (“to (re)move, change, vary, mutate, exchange, abandon”). Doublet of mute and mutate. The unetymological ⟨l⟩ was introduced into the spelling by mistakenly assuming a French origin with -l- as in fault and vault; compare solder, which in contrast has an etymological ⟨l⟩ (from Latin solidāre, “to make solid“) but was historically pronounced without that grapheme's sound.