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
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
Without clear communication from management, early skepticism can harden into quiet resistance.
—
Benjamin Laker, Forbes.com, 12 May 2025
While the healing process can be beneficial in securing the implant in place, the scar tissue can also harden and contract around the insert, causing difficulties in regards to aesthetics — as well as pain — per the site.
—Michelle Lee, People.com, 12 May 2025
Now, with legal challenge after legal challenge, more and more people are getting hardened against this, and saying, ‘This isn’t O.K.
—Jessica Winter, New Yorker, 10 May 2025
With both sides hardening their positions, the risk of open conflict is growing, and the coming weeks may determine whether de-escalation is possible—or if confrontation becomes inevitable.
—Amir Daftari, MSNBC Newsweek, 9 May 2025
See All Example Sentences for harden
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Benjamin Laker, Forbes.com, 12 May 2025
While the healing process can be beneficial in securing the implant in place, the scar tissue can also harden and contract around the insert, causing difficulties in regards to aesthetics — as well as pain — per the site.
—Michelle Lee, People.com, 12 May 2025
Now, with legal challenge after legal challenge, more and more people are getting hardened against this, and saying, ‘This isn’t O.K.
—Jessica Winter, New Yorker, 10 May 2025
With both sides hardening their positions, the risk of open conflict is growing, and the coming weeks may determine whether de-escalation is possible—or if confrontation becomes inevitable.
—Amir Daftari, MSNBC Newsweek, 9 May 2025
See All Example Sentences for harden
Cite this Entry
“Harden.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harden. Accessed 20 May. 2025.
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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share