noun (n)

• motivation based on ideas of right and wrong(noun.motive)

  Synonym:
  ethical motive, morality, morals
  

  source: wordnet30
• the philosophical study of moral values and rules(noun.cognition)

  Synonym:
  moral philosophy
  

  source: wordnet30
• The science of human duty; the body of rules of duty drawn from this science; a particular system of principles and rules concerting duty, whether true or false; rules of practice in respect to a single class of human actions; as, political or social ethics; medical ethics.(noun)

  source: webster1913