Lewis & Short

dē-ruptus, a, um, Part. [derumpo, not in use], broken; hence, like abruptus, of localities, precipitous, steep (not before Lucret.): dextra pars (maceriae) in aliquantum altitudinis, Liv. 42, 15; so, saxa, Lucr. 6, 539: ripae, Liv. 37, 39: angustiae (with praecipites), id. 21, 33: collis (with arduus), Tac. A. 2, 80: spatia terrae (with prona), Gell. 7, 2, 11.
Comp.: in deruptiorem tumulum, Liv. 38, 2.
Sup. and adv. appear not to occur.

      1. b. In plur. subst., dērupta, ōrum, n., precipices: in derupta praecipitati, Liv. 38, 2 fin.: per derupta et avia, Tac. A. 4, 45; 6, 21.