Definition of harden

• v. t. - To make hard or harder; to make firm or compact; to indurate; as, to harden clay or iron.
• v. t. - 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.
• v. i. - To become hard or harder; to acquire solidity, or more compactness; as, mortar hardens by drying.
• v. i. - To become confirmed or strengthened, in either a good or a bad sense.