A chasm or gulf with steep sides. “Over the vast abrupt.” [This use of the word is infrequent.

Literally, broken off, or broken short. Hence,

Steep, craggy; applied to rocks, precipices and the like.

Figuratively, sudden; without notice to prepare the mind for the event; as an abrupt entrance and address.

Unconnected; having sudden transitions from one subject to another; as an abrupt style: .

In botany, an abrupt pinnate leaf is one which has neither leaflet, nor entril at the end.