Lewis Short
(adjective) : in-sŭpĕrābĭlis, e
* That cannot be passed over.
* Lit., insurmountable: transitus Alpium,Liv. 21, 23: via,id. ib. 36.
* Transf.
* Unconquerable: genus bello,Verg. A. 4, 40; cf.: caput bello,Ov. M. 12, 613.— Of a disease, incurable: valetudo,Plin. Ep. 2, 2.
* Unavoidable, inevitable: fatum,Ov. M. 15, 807: necessitas fati,Gell. 13, 1.—Adv.: insŭpĕrābĭ-lĭter, unconquerably, Aug. Civ. Dei, 5, 8.
Charlton T. Lewis, Charles Short, A Latin Dictionary