harden

Verb

• cause to accept or become hardened to; habituate
  • He was inured to the cold
    

• make fit
  • This trip will season even the hardiest traveller
    

• harden by reheating and cooling in oil
  • temper steel
    

• make hard or harder
  • The cold hardened the butter
    

• become hard or harder
  • The wax hardened
    

Related words

• Synonyms: 
  inure , indurate , season , temper