verb (used with object)
- to make hard or harder: to harden steel.
- to make pitiless or unfeeling: to harden one’s heart.
- to make rigid or unyielding; stiffen: The rigors of poverty hardened his personality.
- to strengthen or confirm, especially with reference to character, intentions, feelings, etc.; reinforce.
- to make hardy, robust, or capable of endurance; toughen.
- Military. to reinforce the structure of (a military or strategic installation) to protect it from nuclear bombardment.
verb (used without object)
- to become hard or harder.
- to become pitiless or unfeeling.
- to become rigid or unyielding; stiffen: His personality hardened over the years.
- to become confirmed or strengthened: His resistance hardened.
- to become inured or toughened: The troops hardened under constant fire.
- Commerce. (of a market, prices, etc.)
- to cease to fluctuate; firm: When the speculators withdrew from the market, the prices hardened.
- to rise higher.
- Sir Arthur,1865–1940, English biochemist: Nobel Prize 1929.
- to make or become hard or harder; freeze, stiffen, or set
- to make or become more hardy, tough, or unfeeling
- to make or become stronger or firmerthey hardened defences
- to make or become more resolute or sethardened in his resolve
- (intr) commerce
- (of prices, a market, etc) to cease to fluctuate
- (of price) to rise higher
- a rough fabric made from hards
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.