a. Experienced in combat, and therefore more effective at fighting; -- used mostly of infantry troops; as, battle-hardened veterans.
Syn. -- combat-hardened, combat-tested. [ PJC ]

v. t. 1. To subject to a process which converts the surface of iron into steel. [ 1913 Webster ]

2. To render insensible to good influences. [ 1913 Webster ]

a. 1. Having the surface hardened, as iron tools. [ 1913 Webster ]

2. Hardened against, or insusceptible to, good influences; rendered callous by persistence in wrongdoing or resistance of good influences; -- said of persons. [ 1913 Webster ]

n. The act or process of converting the surface of iron into steel. Ure. [ 1913 Webster ]

☞ Casehardening is now commonly effected by cementation with charcoal or other carbonizing material, the depth and degree of hardening (carbonization) depending on the time during which the iron is exposed to the heat. See Cementation. [ 1913 Webster ]

v. t. [ Pref. en- + harden: cf. F. enhardir to embolden. ] To harden; to embolden. [ Obs. ] Howell. [ 1913 Webster ]

v. t. to harden (steel) by adding carbon. [ WordNet 1.5 ]

v. t. To harden, as a metal, by hammering it in the cold state. [ 1913 Webster ]

v. t. [ imp. & p. p. Hardened p. pr. & vb. n. Hardening ] [ OE. hardnen, hardenen. ] 1. To make hard or harder; to make firm or compact; to indurate; as, to harden clay or iron. [ 1913 Webster ]

2. To accustom by labor or suffering to endure with constancy; to strengthen; to stiffen; to inure; also, to confirm in wickedness or shame; to make unimpressionable. “Harden not your heart.” Ps. xcv. 8. [ 1913 Webster ]

I would harden myself in sorrow. Job vi. 10. [ 1913 Webster ]

v. i. 1. To become hard or harder; to acquire solidity, or more compactness; as, mortar hardens by drying. [ 1913 Webster ]

The deliberate judgment of those who knew him [ A. Lincoln ] has hardened into tradition. The Century. [ 1913 Webster ]

2. To become confirmed or strengthened, in either a good or a bad sense. [ 1913 Webster ]

They, hardened more by what might most reclaim. Milton. [ 1913 Webster ]

prop. n. A small genus of Australian woody vines with small violet flowers; closely related to genus Kennedia.
Syn. -- genus Hardenbergia. [ WordNet 1.5 ]

a. 1. Made hard, or harder, or compact; made unfeeling or callous; made obstinate or obdurate; confirmed in error or vice.

2. Rendered resistant to the effects of nearby explosions; as, a hardened missile silo; hardened warhead electronics. [ PJC ]

3. Experienced and inured to hardship; as, hardened combat troops. [ PJC ]

4. Strongly habituated to a certain type of behavior, and unlikely to change; as, a hardened criminal. Usually used only of behavior perceived negatively. [ PJC ]

Syn. -- Impenetrable; hard; obdurate; callous; unfeeling; unsusceptible; insensible. See Obdurate. [ 1913 Webster ]

n. One who, or that which, hardens; specif., one who tempers tools. [ 1913 Webster ]

n. 1. Making hard or harder. [ 1913 Webster ]

2. That which hardens, as a material used for converting the surface of iron into steel. [ 1913 Webster ]

v. t. To harden too much; to make too hard. Boyle. [ 1913 Webster ]

a. (Metal.) Designating, or pert. to, any of various steels that harden when heated to above a red heat and cooled in air, usually in a blast of cold air with moderate rapidity, without quenching. Such steels are alloys of iron and carbon with manganese, tungsten and manganese, chromium, molybdenum and manganese, etc. They are chiefly used as high-speed steels. -- Self`-hard"en*ed, a. [Webster 1913 Suppl.]