hardened; hardening
ˈhärd-niŋ 
ˈhär-dᵊn-iŋ
1
: to make hard or harder
2
: to confirm in disposition, feelings, or action
especially
: to make callous
hardened his heart
3
4
: to protect from blast, heat, or radiation (as by a thick barrier or placement underground)
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
Synonyms
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 on the Web
The photoinitiators in gel polish absorb UV light to harden and consecrate its final form.
—
Rosa Jisoo Pyo, Vogue, 11 June 2024
Others, fabricated from translucent amber resin that has hardened to a glossy sheen, are low and horizontal, oozing and puddling across the floor like pools of blood or toxic spills.
—Christopher Knight, Los Angeles Times, 22 May 2024
In the information domain, Taiwan should harden its communication systems and train a more sophisticated cyberdefense workforce.
—Isaac Kardon, Foreign Affairs, 21 May 2024
Boudreaux has been spotlighting his decades of law-and-order experience and is promising to harden the nation's porous border.
—CBS News, 21 May 2024
See all Example Sentences for harden 
Rosa Jisoo Pyo, Vogue, 11 June 2024
Others, fabricated from translucent amber resin that has hardened to a glossy sheen, are low and horizontal, oozing and puddling across the floor like pools of blood or toxic spills.
—Christopher Knight, Los Angeles Times, 22 May 2024
In the information domain, Taiwan should harden its communication systems and train a more sophisticated cyberdefense workforce.
—Isaac Kardon, Foreign Affairs, 21 May 2024
Boudreaux has been spotlighting his decades of law-and-order experience and is promising to harden the nation's porous border.
—CBS News, 21 May 2024
See all Example Sentences for harden
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'harden.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near harden
Cite this Entry
“Harden.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harden. Accessed 17 Jun. 2024.
Copy CitationKids Definition
harden
verb
hard·en
ˈhärd-ᵊn
hardened; hardening
ˈhärd-niŋ
-ᵊn-iŋ
1
: to make or become hard or harder
2
: to make unfeeling or unsympathetic
hardened his heart
3
: to make or become hardy or strong
muscles hardened by exercise
4
: to protect from blast, heat, or radiation (as by a thick barrier or by placing underground)
hardened missile sites
5
a
: to become firm, stable, or settled
b
: to express harshness
hardener
noun
ˈhärd-nər
-ᵊn-ər
Biographical Definition
Harden
2 of 2biographical name (2)
Maximilian 1861–1927 originally Felix Ernst Witkowski German writer
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