/ ˈmʌfl; NAmE / verb [ vn ]
1.
to make a sound quieter or less clear :
He tried to muffle the alarm clock by putting it under his pillow.
2.
muffle sb/sth (up) in sth to wrap or cover sb/sth in order to keep them / it warm :
She muffled the child up in a blanket.
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WORD ORIGIN
late Middle English (as a verb): perhaps a shortening of Old French enmoufler ; the noun (mid 17th cent.) from Old French moufle thick glove.