Synonyms of harden

harden

verb

ˈhär-dᵊn 

1

as in to freeze

to become physically firm or solid

the glue begins to harden as soon as it is exposed to air

Synonyms & Similar Words

• freeze
• stiffen
• solidify
• congeal
• concrete
• indurate
• firm (up)
• set
• thicken
• gel
• crystallize
• encrust
• coagulate
• cake
• gelatinize
• jell
• calcify
• ossify
• petrify
• rigidify
• callus
• anneal
• temper
• clot
• jelly
• gelate
• case-harden

Antonyms & Near Antonyms

• soften
• liquefy
• melt
• dissolve
• thaw
• smelt
• fuse
• flux
• unfreeze
• deliquesce

2

as in to strengthen

to make able to withstand physical hardship, strain, or exposure

pioneer women who had been hardened by years of living on the plains

Synonyms & Similar Words

• strengthen
• fortify
• toughen
• steel
• inure
• adjust
• season
• indurate
• adapt
• bolster
• reinforce
• acclimate
• temper
• anneal
• invigorate
• enforce
• brace
• vitalize
• acclimatize
• immunize
• accustom
• buttress
• habituate
• condition
• boost
• break in
• prop (up)
• support
• naturalize
• train
• forearm
• limber (up)

Antonyms & Near Antonyms

• soften
• weaken
• exhaust
• sap
• emasculate
• cripple
• incapacitate
• hamstring
• sensitize
• enfeeble
• enervate
• debilitate

3

as in to toughen

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 & Similar Words

• strengthen
• toughen
• fortify
• beef (up)
• temper
• anneal
• energize
• invigorate
• tone (up)
• vitalize
• firm (up)
• restrengthen

Antonyms & Near Antonyms

• weaken
• hurt
• impair
• paralyze
• cripple
• injure
• harm
• damage
• debilitate
• enervate
• enfeeble
• undermine
• incapacitate
• break down
• wear out
• undercut
• sap

4

as in to stiffen

to make more harsh, uncompromising, or severe

the government hardened restrictions on travel to and from the war-torn nation

Synonyms & Similar Words

• stiffen
• strengthen
• toughen
• harshen

Antonyms & Near Antonyms

• ease
• lessen
• soften
• ameliorate
• moderate

Example Sentences

Recent Examples of harden

The incident could further inflame tensions between the Koreas, which have no working military hotlines or other emergency communications channels as North Korea hardens its stance toward Seoul while expanding its military nuclear program. — Arkansas Online, 1 Oct. 2026

The country’s elites have been hardened by the war, which killed their friends and family members. — Mohammad Ayatollahi Tabaar, Foreign Affairs, 1 Oct. 2026

Nearly all Senate Democrats voted to require the State Department to report on Israeli settler violence in the West Bank, in a continuing sign of the party’s hardening stance toward Israel. — Noah Robertson, Washington Post, 30 Sep. 2026

After the attack, flight deck doors were hardened to provide a significant barrier against anyone outside the cockpit trying to get in. — Jeff Price, The Conversation, 30 Sep. 2026