clam dampen deaden dull extinguish gag hush lull muffle mute muzzle overawe quash quell quiet shush soft-pedal squelch stifle still subdue suppress tongue-tie choke off clam up close up cool it cut off cut short decrease the volume dry up dumb dummy up hold one's tongue hush one's mouth hush-hush keep it down pipe down quiet down say nothing shut up sit on strike dumb