harden

verb hard·en \ ˈhär-dᵊn \

Updated on: 1 Dec 2017

Definition of harden

hardened; hardening play \ˈhärd-niŋ, ˈhär-dᵊn-iŋ\

transitive verb

1 : to make hard or harder

2 : to confirm in disposition, feelings, or action; especially : to make callous

hardened his heart

3 a : inure, toughen

harden troops

b : to inure to unfavorable environmental conditions (such as cold) —often used with off

harden off seedlings before transplanting

4 : to protect from blast, heat, or radiation (as by a thick barrier or placement underground)

intransitive verb

1 : to become hard or harder

2 a : to become firm, stable, or settled

b : to assume an appearance of harshness or severity

her face hardened at the thought

3 : to become gradually acclimatized to unfavorable conditions —often used with off

plants hardened off before the first frost

See harden defined for English-language learners

See harden defined for kids

Examples of harden in a Sentence

The presence of certain substances in the blood can cause the arteries to harden.
These additives are designed to harden the steel.
substances that can harden the arteries
The news has hardened opposition to the government.
He had been hardened by his years of military service.

Recent Examples of harden from the Web

Pruning may prompt new growth that won’t have a chance to harden off before winter hits.

— jo ellen meyers sharp, Indianapolis Star, "Hoosier Gardener: Take care not to trim next year's flowers from plants," 13 Oct. 2017
Never attempt to dig out excessive or hardened earwax with available items, such as a paper clip, a cotton swab or a hairpin.

— seattle times staff, The Seattle Times, "Home remedies: Cleaning out the earwax," 26 Sep. 2017
Tungsten, used to harden steel in ballistic missiles and in drill bits, has surged more than 50 percent in the last two months amid growing concern about supply cutbacks in China, where about 80 percent of the metal comes from.

— thomas biesheuvel, Bloomberg.com, "China Sends One of the West’s Most Critical Materials Soaring," 11 Sep. 2017
There was a sense of respect, and it was all done tastefully, never cheapened or hardened—or drab, which was very much the look of a lot of editorial images at the time.

— charlotte cowles, Harper's BAZAAR, "DV: Diana Vreeland," 24 July 2015
The concrete poured for the sections of wall is now hardening ahead of official tests to see if the prototypes can be scaled, dug under or simply blown up.

— miguel marquez and rosalina nieves, CNN, "5 opinions from in the shadows of Trump's border wall prototypes," 26 Oct. 2017
The floundering Republican attempt to undo the Affordable Care Act met hardening resistance from key GOP senators Sunday that left it on the verge of collapse even as advocates vowed to keep pushing for a vote this week.

— author: sean sullivan, abby phillip, Alaska Dispatch News, "GOP health bill in major peril as resistance hardens among key senators," 25 Sep. 2017
President Donald Trump on Sunday continued and hardened his crusade against NFL players who protest the national anthem.

— michael mccann, SI.com, "Can President Donald Trump Legally Command the NFL To Fire Players?," 24 Sep. 2017
As the lava cools and hardens, the island extends itself, minute by minute.

— elyse butler, Smithsonian, "Hawaii’s Must-See Lava Flows Are Home to New, Startling Ecosystems," 29 Apr. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'harden.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of harden

13th century

harden Synonyms

Synonyms

concrete, congeal, firm (up), freeze, indurate, set, solidify

Antonyms

liquefy (also liquify), soften

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

Harden

biographical name Har·den \ ˈhär-dᵊn \

Definition of Harden

Sir Arthur 1865–1940 English chemist

Harden

biographical name

Definition of Harden

Maximilian 1861–1927 originally Felix Ernst Witkowski German writer

HARDEN Defined for English Language Learners

harden

verb

Definition of harden for English Language Learners

: to become hard or firm or to make (something) hard or firm
: to become more definite and strongly felt or to make (something) more definite and strongly felt
: to make (someone) hard : to make (someone) less emotional and less likely to feel sorry for other people