harden

Synonyms: amalgamate anneal bake brace buttress cake calcify callous cement close clot coagulate compact congeal consolidate contract crystallize curdle densify dry firm fix fortify fossilize freeze gird indurate jell nerve ossify petrify precipitate press reinforce set settle solidify starch steel stiffen strengthen temper thicken toughen vitrify

Antonyms: liquefy melt soften

Synonyms: 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

Antonyms: be intolerant indulge spoil