(adjective) : in-stăbĭlis, e
* That does not stand fast, unsteady, unstable, tottering, not firm (mostly poet.; syn. varius, mutabilis, vagus; not in Cic.).
* Lit.: sic erat instabilis tellus,Ov. M. 1, 16: locus ad gradum instabilis,Tac. A. 1, 64: (with lubricus) gradus,Curt. 8, 11, 13: ingressus,Liv. 24, 34, 15: vestigium,Plin. Pan. 22, 4: volutatio,Plin. 31, 6, 33, § 63: cymbae,Verg. G. 4, 195: naves,Curt. 4, 2, 9.—Transf., unsteady, i. e. that does not keep its ground: (with fluctuans) acies,Liv. 9, 35, 6: hostis,id. 27, 18, 14.
* Trop., unstable, inconstant, changeable, fickle: insanam aiunt (Fortunam), quia atrox, incerta instabilisque sit, Pac. ap. Auct. Her. 2, 23, 36: res maritimae celerem atque instabilem mo tum habent, Caes. B. G. 4, 23: nihil tam instabile ac fluxum est, quam fama,Tac. A. 13, 19: fortuna,id. H. 4, 47: conjugium,Juv. 9, 79: animus,Verg. G. 4, 105 (but read insatiabiles, Curt. 7, 8, 19). — Adv.: instă-bĭlĭter, unsteadily, Aug. Conf. 13, 20.

s. TLL