startle

Noun

• a sudden involuntary movement
  • he awoke with a start
    

Verb

• move or jump suddenly, as if in surprise or alarm
  • She startled when I walked into the room
    

• to stimulate to action
  • ..startled him awake
    
  • galvanized into action
    

Related words

• Synonyms: 
  jump , start , galvanize , galvanise