Harden

[hahr-dn] /ˈhɑr dn/

verb (used with object)
1.
to make or harder:
to harden steel.
2.
to make pitiless or unfeeling:
to harden one’s heart.
3.
to make rigid or unyielding; stiffen:
The rigors of poverty hardened his personality.
4.
to strengthen or confirm, especially with reference to character, intentions, feelings, etc.; reinforce.
5.
to make hardy, robust, or capable of endurance; toughen.
6.
Military. to reinforce the structure of (a military or strategic installation) to protect it from nuclear bombardment.
verb (used without object)
7.
to become hard or harder.
8.
to become pitiless or unfeeling.
9.
to become rigid or unyielding; stiffen:
His personality hardened over the years.
10.
to become confirmed or strengthened:
His resistance hardened.
11.
to become inured or toughened:
The troops hardened under constant fire.
12.
Commerce.

[hahr-dn] /ˈhɑr dn/
noun
1.
Sir Arthur, 1865–1940, English biochemist: Nobel Prize 1929.
/ˈhɑːdən/
verb
1.
to make or become hard or harder; freeze, stiffen, or set
2.
to make or become more hardy, tough, or unfeeling
3.
to make or become stronger or firmer: they hardened defences
4.
to make or become more resolute or set: hardened in his resolve
5.
(intransitive) (commerce)

/ˈhɑːdən/
noun
1.
a rough fabric made from hards
n.

c.1200 (replacing Old English heardian) “to make (something) hard,” from hard + -en (1). Meaning “to become hard” is late 14c. Related: Hardened (figurative sense of “unfeeling” is from late 14c.); hardening.