What is the meaning of hissing?

noun

• A fricative sound (especially as an expression of disapproval. )
  • usage: "the performers could not be heard over the hissing of the audience"
  • synonyms: hiss, hushing, fizzle, sibilation

verb

• Make a sharp hissing sound, as if to show disapproval.
  • synonyms: hiss, siss, sizz, sibilate
• Move with a whooshing sound.
  • synonyms: hiss, whoosh
• Express or utter with a hiss.
  • synonyms: hiss, sizz, siss, sibilate
• Show displeasure, as after a performance or speech.
  • synonyms: boo, hiss