Similar word to caseharden:

acclimate, acclimatize, adapt, adjust, blunt, brutalize, callous, callus, case-harden, climatize, coarsen, conform, deaden, develop, discipline, dull, embitter, habituate, indurate, inure, make callous, numb, paralyze, render insensitive, roughen, season, steel, stiffen, strengthen, stun, stupefy, teach, train