Definition of 'harden'
- become hard or harder; "The wax hardened"
- make hard or harder; "The cold hardened the butter"
- harden by reheating and cooling in oil; "temper steel"
- make fit; "This trip will season even the hardiest traveller"
- cause to accept or become hardened to; habituate; "He was inured to the cold"
Synonyms: inure indurate