noun (n)

• a fricative sound (especially as an expression of disapproval)(noun.event)

  Example:
  The performers could not be heard over the hissing of the audience.
  

  Synonym:
  fizzle, hiss, hushing, sibilation
  

  source: wordnet30
• The act of emitting a hiss or hisses.(noun)

  source: webster1913