ETYM Latin abruptus, p. p. of abrumpere to break off; ab + rumpere to break. Related to Rupture.
1. Exceedingly sudden and unexpected.
2. Extremely steep; SYN. precipitous, sharp.
3. Marked by sudden changes in subject and sharp transitions; SYN. disconnected.
4. Surprisingly and unceremoniously brusque in manner.

ETYM Old Eng. sodian, sodein, Old Fren. sodain, sudain, French soudain, Latin subitaneus, from subitus sudden, that has come unexpectedly, p. p. of subire to come on, to steal upon; sub under, secretly + ire to go. Related to Issue, Subitaneous.
Happening without warning or in a short space of time.