hardenv. t.[OE. hardnen, hardenen.]1. To make hard or harder; to make firm or compact; to indurate; as, to harden clay or iron.()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.(Ps. xcv. 8.)I would harden myself in sorrow. (Job vi. 10.)v. i.1. To become hard or harder; to acquire solidity, or more compactness; as, mortar hardens by drying.()The deliberate judgment of those who knew him [A. Lincoln] has hardened into tradition. (The Century.)2. To become confirmed or strengthened, in either a good or a bad sense.()They, hardened more by what might most reclaim. (Milton.)