This side trip was unplanned, but enjoyable.
The unplanned work caused a lot of havoc. Because of that, the predictability went down.
Here are some sentences.
That was an unplanned reaction.
Her trip was unplanned.
This is unplanned.
Unplanned.
ed
UNPLANNED
accidental unintentional
Random
odd, stray, unplanned
unplanned off-the-cuff impromptu
Probably unknown.
This is likely the word "accident" (an unplanned or unexpected occurrence).
Unanticipated, unexpected, random and happenstance to name a few.
The correct spelling is "acceded." It means to agree to a demand, request, or treaty.