out of the blue
unannounced
unanticipated
unforeseen
unheralded
unhoped
unhoped-for
unlooked-for
unpredicted
unprovided for
unthought
unthought-of
upset
abrupt
accidental
adventitious
aleatory
antic
breakaway
casual
causeless
chance
chancy
contingent
destinal
dicey
electrifying
extraordinary
fanciful
fantastic
fatal
fatidic
fluky
fortuitous
hasty
headlong
iffy
impetuous
impossible
improbable
impulsive
incidental
incomprehensible
inconceivable
incredible
indeterminate
more than expected
nerve-shattering
offbeat
out-of-the-way
past expectation
precipitant
precipitate
precipitous
quick
rare
recherche
risky
shocking
speedy
startling
sudden
considerable
affected
connected
corrected
defected
deflected
dejected
detected
directed
disaffected
disconnected
disrespected
effected
ejected
elected
erected
expected
infected
injected
inspected
interconnected
interjected
intersected
misdirected
neglected
protected
recollected
reconnected
redirected
reelected
reflected
rejected
respected
resurrected
selected
subjected
suspected
unaffected
uncollected
unconnected
uncorrected
undetected
unelected
uninfected
unprotected
unsuspected