Answer: hisses

AnswerCrossword Clue
HISSES

Greets the villain

HISSES

Audience disapproval

HISSES

Snake speech

HISSES
Leak indicators, perhaps
HISSES
Sibilant catcalls
HISSESGreets the bad guy
HISSESWarnings from a ticked-off tabby
HISSESCatcalls
HISSESRelatives of boos
HISSESVillain's greeting
HISSESSnake sounds
HISSESShows disapproval, in a way
HISSESChorus for the villain
HISSESRadiator sounds
HISSESSounds of disapproval
HISSESShows disapproval
HISSESSnakes' sounds
HISSESSounds from racers
HISSESStage villain's reward.
HISSES"Mellerdrammer" sounds.
HISSESGallery sounds.
HISSESSounds from the gallery
HISSESOphidian sounds
HISSESSteam-bath sounds
HISSESVillain's earful
HISSESAudio problems
HISSESRadiator output
HISSESSounds from steam irons
HISSESCat warnings
HISSESSerpent's warnings
HISSESSounds from a snake pit
HISSESBoos' partner
HISSESSigns of audience disapproval
HISSESBoos' partners
HISSESMakes like a snake
HISSESUnwanted crowd sounds