noun (n)

• something that incites or provokes; a means of arousing or stirring to action(noun.motive)

  Synonym:
  incitement, provocation
  

  source: wordnet30
• an act of urging on or spurring on or rousing to action or instigating(noun.act)

  Synonym:
  incitement
  

  source: wordnet30
• The act of inciting or moving to action.(noun)

  source: webster1913