Lewis & Short

immōtus (inm-), a, um, adj. [in-motus], unmoved, immovable, motionless (mostly poet. and in post-Aug. prose).

  1. I. Lit.: (illa arbor) immota manet, Verg. G. 2, 293: (Ceres) Sub Jove duravit multis immota diebus, Ov. F. 4, 505: supercilia (opp. mobilia), Quint. 11, 3, 79: sceptrum, id. ib. § 158: aquae, i. e. frozen, Ov. Tr. 3, 10, 38: aër, Plin. 17, 24, 36, § 222: apum examina, Col. 9, 4, 19: serenus et immotus dies, calm, Tac. H. 1, 86; Plin. Ep. 2, 7, 6; id. Pan. 82: terrarum pondus sedet immotum, Sen. Prov. 1, 2: mare, id. Suas. 1, 1: cervix, id. ib. 6, 17: legio, Tac. A. 14, 37: vultus, id. ib. 2, 29.
  2. II. Trop., unmoved, unshaken, undisturbed, steadfast, firm: mens immota manet, Verg. A. 4, 449: manent immota tuorum Fata tibi, id. ib. 1, 257; cf.: immota manet fatis Lavinia conjux, id. ib. 7, 314: immotas praebet mugitibus aures, unmoved, Ov. M. 15, 465: nympha procis, Val. Fl. 5, 112: adversus turmas acies, Liv. 10, 14, 16; 21, 55, 10: immotus iis, Tac. A. 15, 59: immota aut modice lacessita pax, id. ib. 4, 32: fides sociis, Val. Fl. 3, 598: felicis animi immota tranquillitas, Sen. de Ira, 2, 12, 6: constantia, id. Const. 5, 4: gaudium, id. Vit. Beat. 4, 5: animus, Lact. 6, 17, 22.
    In neutr.: si mihi non animo fixum immotumque sederet, Ne, etc., immovable, unchangeable, Verg. A. 4, 15; so with an object-clause: immotum adversus eos sermones fixumque Tiberio fuit non omittere caput rerum, Tac. A. 1, 47.