harden

1 to become physically firm or solid the glue begins to harden as soon as it is exposed to air Synonyms concrete, congeal, firm (up), freeze, indurate, set, solidify Related Words cake, callus, encrust (also incrust); clot, coagulate, gel, gelate, gelatinize, jell, jelly, stiffen, thicken; calcify, crystallize (also crystalize), ossify, petrify, rigidify; anneal, case-harden, temper Near Antonyms deliquesce, dissolve, flux, fuse, melt, smelt, thaw, unfreeze Antonyms liquefy (also liquify), soften

2 to make able to withstand physical hardship, strain, or exposure pioneer women who had been hardened by years of living on the plains Synonyms fortify, indurate, inure, season, steel, strengthen, toughen Related Words acclimate, acclimatize, adapt, adjust; anneal, temper; invigorate, vitalize; immunize; bolster, boost, brace, buttress, enforce, forearm, prop (up), reinforce (also reenforce), support; break in, limber (up), train; accustom, condition, habituate, naturalize Near Antonyms emasculate, enervate, enfeeble, exhaust, sap, weaken; cripple, debilitate, hamstring, incapacitate; sensitize Antonyms soften

3 to increase the ability of (as a muscle) to exert physical force arm muscles that were hardened by all the years of casting and hauling his fishing nets Synonyms beef (up), fortify, strengthen, toughenRelated Words anneal, temper; firm (up), tone (up); energize, invigorate, vitalize; restrengthenNear Antonyms cripple, incapacitate, paralyze; damage, harm, hurt, impair, injure; break down, wear out; sap, undercut, undermineAntonyms debilitate, enervate, enfeeble, weaken

4 to make more harsh, uncompromising, or severe the government hardened restrictions on travel to and from the war-torn nation Synonyms harshen, stiffen, strengthen, toughenNear Antonyms lessen, moderate, softenAntonyms ameliorate, ease