startling (adj.)

• abrupt
• alarming
• amazing
• astonishing
• astounding
• awesome
• awing
• breathtaking
• chilling
• confounding
• daunting
• deterrent
• disconcerting
• discouraging
• disheartening
• dismaying
• disquieting
• disturbing
• electrifying
• fearful
• fearsome
• frightening
• frightful
• hasty
• headlong
• impetuous
• impulsive
• jarring
• jolting
• mind-boggling
• overwhelming
• precipitant
• precipitate
• precipitous
• quick
• scary
• shocking
• spectacular
• speedy
• staggering
• stunning
• sudden
• surprising
• swift
• terrifying
• unanticipated
• unexpected
• unforeseen
• unlooked-for
• unpredicted
• upsetting