Lewis Short
(adjective) : ĭn-excūsābĭlis, e
* That cannot be excused, inexcusable (poet. and post-class.): ne te retrahas, et inexcusabilis absis,Hor. Ep. 1, 18, 58: tempus,Ov. M. 7, 511: onera,that cannot be refused,Dig. 5, 1, 50: necessitas, Cod. Th. 11, 16, 7 al.—Comp., Ambros. de Vocat. Gent. 2, 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary