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

adjective. Rendered resistant to the effects of nearby explosions.

adjective. Experienced and inured to hardship.

adjective. Strongly habituated to a certain type of behavior, and unlikely to change. Usually used only of behavior perceived negatively.

verb. Simple past tense and past participle of harden.

adjective. Unfeeling or lacking emotion due to experience; callous.

adjective. protected against attack (especially by nuclear weapons)

adjective. converted to solid form (as concrete)

adjective. used of persons; emotionally hardened

adjective. made tough by habitual exposure

adjective. made hard or flexible or resilient especially by heat treatment