Answer: sudden

AnswerCrossword Clue
SUDDENHasty.
suddenan occurrence without warning
suddenabrupt; quick; unexpected
suddenwithout warning; unexpectedly; suddenly
SUDDENUnforeseen
SUDDENHappening without warning
SUDDENRash
SUDDENUnanticipated
SUDDEN"This is so ...!"
SUDDENAbrupt.
SUDDENPrecipitate.
SUDDENOut of the blue
SUDDENUnforeseen.
SUDDENOut-of-the-blue
SUDDENComing out of the blue
SUDDENQuip, part 3
SUDDENLike a sneak attack
SUDDEN... death (game-ending point)
SUDDENUnexpected
SUDDEN"This is so ..!"
SUDDENWithout warning
SUDDENAbrupt