Adverb
without advance planning
in a way that was not expected
Source: WordNetYes, man is mortal, but that would be only half the trouble. The worst of it is that he's sometimes unexpectedly mortal - there's the trick! Mikhail Bulgakov
The Strange Loop phenomenon occurs whenever, by moving upwards (or downwards) through levels of some hierarchial system, we unexpectedly find ourselves right back where we started. Douglas Hofstadter
I am having a very difficult time. Things happen unexpectedly. Kōki Hirota
I must be permitted to say that I have been almost overwhelmed by the announcement of the sad event which has so recently occurred. I feel incompetent to perform duties so important and responsible as those which have been so unexpectedly thrown upon me. Andrew Johnson
No amount of thought can ever reveal what comes unexpectedly. Arthur Erickson
Sometimes the most beautiful thing is precisely the one that comes unexpectedly and unearned. Anna Freud