From WordNet (r) 2.0 (August 2003) [wn]:
abruptly
adv : quickly and without warning; "he stopped suddenly" [syn:
suddenly, short, dead]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Abruptly \Ab*rupt"ly\, adv.
1. In an abrupt manner; without giving notice, or without the
usual forms; suddenly.
[1913 Webster]
2. Precipitously.
[1913 Webster] Abruptly pinnate