verb (v)

• become hard or harder(verb.change)

  Example:
  The wax hardened.
  

  Synonym:
  indurate
  Antonym:
  soften
  

  source: wordnet30
• make hard or harder(verb.change)

  Example:
  The cold hardened the butter.
  

  source: wordnet30
• harden by reheating and cooling in oil(verb.change)

  Synonym:
  temper
  

  source: wordnet30
• make fit(verb.change)

  Synonym:
  fit, season
  

  source: wordnet30
• cause to accept or become hardened to; habituate(verb.change)

  Synonym:
  indurate, inure
  

  source: wordnet30
• To make hard or harder; to make firm or compact; to indurate; as, to harden clay or iron.(verb)

  source: webster1913
• To become hard or harder; to acquire solidity, or more compactness; as, mortar hardens by drying.(verb)

  source: webster1913