Answer: peeker

AnswerCrossword Clue
PEEKERBlindman's buff cheater
PEEKERCheater, perhaps
PEEKEROne who looks in advance
PEEKEROne who shouldn't be looking
PEEKERSurprise spoiler, perhaps
PEEKERHide-and-seek cheater
PEEKEROne at a keyhole maybe
PEEKERBlind man's buff cheater