Answer: pipedown

AnswerCrossword Clue
PIPEDOWN"Shh!" from a plumber?
PIPEDOWN"Put a lid on it!"
PIPEDOWN"Zip it!"
PIPEDOWN"Shush!"
PIPEDOWNQuiet, please!
PIPEDOWNDirective
PIPEDOWNGag order?
PIPEDOWNVoice command?
PIPEDOWN"Not so loud!"