Mawson, C.O.S., ed. (1870–1938). Roget’s International Thesaurus. 1922.

Class VI. Words Relating to the Sentient and Moral Powers
Section IV. Moral Affections
3. Moral Conditions

951. Impenitence.

   NOUN:IMPENITENCE, irrepentance, recusancy, recusance; lack of contrition.
  hardness of heart, heart of stone, seared conscience, induration, obduracy; deaf ears.
   VERB:BE IMPENITENT &c. adj.; steel the heart, harden the heart; turn away from the light; die game, die and make no sign.
   ADJECTIVE:IMPENITENT, uncontrite, obdurate, hard, hardened, seared, recusant, unrepentant; relentless, remorseless, graceless, shriftless.
  lost, incorrigible, irreclaimable.
  unreclaimed, unreformed; unrepented, unatoned.
   QUOTATION:The good die first, And they whose hearts are dry as summer dust Burn to the socket.—Wordsworth