noun (n)

• a remote or indirect consequence of some action(noun.phenomenon)

  Example:
  His declaration had unforeseen repercussions.
  

  Synonym:
  reverberation
  

  source: wordnet30
• a movement back from an impact(noun.event)

  Synonym:
  backlash, rebound, recoil
  

  source: wordnet30
• The act of driving back, or the state of being driven back; reflection; reverberation; as, the repercussion of sound.(noun)

  source: webster1913