Answer: hissing

AnswerCrossword Clue
HISSINGBlowing off steam?
HISSINGBooing's accompaniment
HISSINGAudience reaction, at times
HISSINGSound of disapproval
HISSINGOminous jungle sound
HISSINGShowing disapproval, in a way
HISSINGSounding like a mad cat
hissingan object of scorn
hissingto make a prolonged s sound
hissingto express disapproval in this way
hissingthe act of emitting a hiss
hissingthe sound of a hiss
hissinghissing sound