startle

(noun) a sudden involuntary movement. Synonyms: jump, start. Example: "He awoke with a start."

(verb) to stimulate to action . Synonyms: galvanize, galvanise. Examples: "..startled him awake." "Galvanized into action."

(verb) move or jump suddenly, as if in surprise or alarm. Synonyms: jump, start. Example: "She startled when i walked into the room."