assibilate assibilation black out buzz censor choke choke off dumbfound effervesce effervescence effervescing fizz fizzle fizzling frication frictional rustling gag hiss hissing hugger-mugger hush hush up hush-hush hushing kill lisp muffle muzzle put to silence quash quiet quieten repress rhonchus shushing shut down on shut up sibilance sibilate sibilation siffle sigmatism silence siss sissing sit on sizz sizzle sizzling smother sneeze sneezing sniff sniffle snore snort snuff snuffle soft-pedal spit splutter sputter squash squelch squish sternutation stertor stifle still strangle strike dumb suppress swish throttle wheeze whish whistle whistling white noise whiz whoosh zip