noun (n)

• anything that tends to arouse(noun.cognition)

  Synonym:
  fillip
  

  source: wordnet30
• an additional payment (or other remuneration) to employees as a means of increasing output(noun.possession)

  Synonym:
  incentive
  

  source: wordnet30
• A premium given for a loan, or for a charter or other privilege granted to a company; as the bank paid a bonus for its charter.(noun)

  source: webster1913