See muffle in Webster's New World Roget's A-Z Thesaurus II
verb
To decrease or dull the sound of:
dampen, deaden, mute, stifle. See increase, soundsTo hold (something requiring an outlet) in check:
burke, choke (back), gag, hold back, hold down, hush (up), quench, repress, smother, squelch, stifle, strangle, suppress, throttle. (Informal) sit on (or upon). See restraint
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