Lewis & Short

in-dūro, āvi, ātum, 1, v. a. and n., to make hard, to harden (poet. and post-Aug.).

  1. I. Act.
    1. A. Lit.: nivem Indurat Boreas, Ov. Tr. 3, 9, 14: sues indurantes attritu arborum costas, Plin. 8, 52, 78, § 212.
    2. B. Trop., to harden, steel: indurandus est animus, Sen. Ep. 51: adversus omnia, quae accidere possunt, id. ib. 4: frontem, to render shameless, id. Ben. 7, 28.
  2. II. Neutr., to become hard, harden: quae (creta) si induraverit, Veg. 3, 82, 2.
    Hence, indūrā-tus, a, um, P. a., hardened.
    1. A. Lit.: robora indurata flammis, Stat. Th. 4, 64.
    2. B. Trop.: induratus praeter spem resistendo hostium timor, Liv. 30, 18, 3: Germanis quid induratius ad omnem patientiam? Sen. Ira, 1, 11.