The word HISSING has appeared in at least 9 clues on different crosswords.

HISSING definition(s):

• the sound of a hiss

• a fricative sound (especially as an expression of disapproval); "the performers could not be heard over the hissing of the audience"

• Present participle of hiss.

• The sound of a hiss.

present participle of hiss

Action by audience may arouse sighs in actors
Blowing off steam?
Ominous jungle sound
"Showing disapproval, in a way"
Snake's noise
Sound of disapproval
Sounding like a mad cat
Booing & ...