1) Accrue 2) Accrue to 3) Accustom 4) Accustom to hardship 5) Accustom, variantly 6) Accustomize 7) Become accustomed 8) Become hardened to 9) Cause to become hardened to 10) Come into effect, legally 11) Come into use 12) Get accustomed to 13) Get hardened 14) Get used to 15) Habituate 16) Habituate or accrue Found on https://www.crosswordclues.com/clue/enure