Answer: hissed

AnswerCrossword Clue
HISSEDGreeted the villain.
hissedto make a prolonged s sound
hissedhissing sound
hissedto express disapproval in this way
hissedHISS, to make a sibilant sound
HISSEDGreeted the bad guy, maybe
HISSEDRazzed
HISSEDDisplayed displeasure
HISSEDSounded angry
HISSEDSounded like a snake
HISSEDShowed disapproval
HISSEDCompanion of booed
HISSEDDisapproved vocally.
HISSEDLet off steam.
HISSEDMade a whistling sound
HISSEDShowed disapproval.
HISSEDExpressed disapproval.
HISSEDRazzed the villain
HISSEDHeckled
HISSEDMade like an asp
HISSEDMade an ophidian sound
HISSEDShowed displeasure
HISSEDBlew off steam?
HISSEDMade sibilant sounds
HISSEDGreeted the villain
HISSEDGave the villain his due
HISSEDWarned, snake-style
HISSEDClearly wasn't pleased