From Latin 'abruptus' (broken off) — the same root 'rumpere' built 'corrupt,' 'erupt,' 'rupture,' and 'bankrupt.'
Sudden and unexpected; brief to the point of rudeness; steep and craggy.
From Latin 'abruptus,' past participle of 'abrumpere' (to break off, to sever), from 'ab-' (away, off) + 'rumpere' (to break). 'Rumpere' derives from PIE *rewp- or *rump- (to snatch, to break), a root also present in Latin 'rupes' (cliff, crag — that which is broken off), 'ruptura' (rupture), and 'corrumpere' (to break apart, corrupt). The PIE root connects further to Greek 'erypein' (to drag away) and possibly Sanskrit 'lumpati' (breaks). English borrowed
Latin 'rumpere' (to break) is one of the most productive roots in English: 'corrupt' (broken thoroughly), 'disrupt' (broken apart), 'erupt' (broken out), 'interrupt' (broken between), 'rupture' (a breaking), and 'bankrupt' (broken bench — a moneylender whose bench was smashed when they failed). 'Abrupt' means 'broken off.'