harden Synonyms

inure indurate season temper reinforce restrengthen roughen sclerosis stiffened set solidified solidifying solidify refrigerate jelly kippered kippering lapidify mineralize naturalize numb orientate ossified ossify petrify steel desensitize acclimatise fossilise firm up dry out brutalise tighten up gel ice over rigidify make stronger weather vulcanize stiffening stiffen strengthen tempered tempering thicken toughened toughening toughen vitrify become rigid