Source : Webster's Revised Unabridged Dictionary (1913)

Hardened \Hard"ened\, a.
   Made hard, or compact; made unfeeling or callous; made
   obstinate or obdurate; confirmed in error or vice.

   Syn: Impenetrable; hard; obdurate; callous; unfeeling;
        unsusceptible; insensible. See {Obdurate}.

Harden \Hard"en\, v. t. [imp. & p. p. {Hardened}; p. pr. & vb.
   n. {Hardening}.] [OE. hardnen, hardenen.]
   1. To make hard or harder; to make firm or compact; to
      indurate; as, to harden clay or iron.

   2. To accustom by labor or suffering to endure with
      constancy; to strengthen; to stiffen; to inure; also, to
      confirm in wickedness or shame; to make unimpressionable.
      ``Harden not your heart.'' --Ps. xcv. 8.

            I would harden myself in sorrow.      --Job vi. 10.

Source : WordNet®

hardened
     adj 1: used of persons; emotionally hardened; "faced a
            case-hardened judge" [syn: {case-hardened}, {hard-boiled}]
     2: made hard or flexible or resilient especially by heat
        treatment; "a sword of tempered steel"; "tempered glass"
        [syn: {tempered}, {treated}, {toughened}] [ant: {untempered}]
     3: made tough by habitual exposure; "hardened fishermen"; "a
        peasant, dark, lean-faced, wind-inured"- Robert Lynd; "our
        successors...may be graver, more inured and equable men"-
        V.S.Pritchett [syn: {enured}, {inured}]
     4: converted to solid form (as concrete) [syn: {set}]