Lewis & Short

dūrābĭlis, e, adj. [duro], lasting, durable (rare; not ante-Aug.): quod caret alterna requie durabile non est, Ov. H. 4, 89; Col. 12, 38, 7; 12, 55, 1: vox, Quint. 11, 3, 23 al.
Comp.: durabilior materies, App. Mag. p. 314, 13.
Sup. does not occur.
Adv.: dūrābĭlĭter, in a lasting manner, Cassiod. Hist. Eccl. 1, 9.