adjective (a)

• made hard or flexible or resilient especially by heat treatment(adj.all)

  Example:
  A sword of tempered steel.
  Tempered glass.
  

  Synonym:
  hardened, toughened, treated
  Antonym:
  unhardened, untempered
  

  source: wordnet30
• adjusted or attuned by adding a counterbalancing element(adj.all)

  Example:
  Criticism tempered with kindly sympathy.
  

  Antonym:
  untempered
  

  source: wordnet30
• Brought to a proper temper; as, tempered steel; having (such) a temper; -- chiefly used in composition; as, a good-tempered or bad-tempered man; a well-tempered sword.(adjective)

  source: webster1913