startle (
http://definr.com/startle)
n : a sudden involuntary movement: "he awoke with a start" [syn:
jump,
start]
v 1: to stimulate to action : "..startled him awake." [syn:
galvanize,
galvanise]
2: move or jump suddenly, as if in surprise or alarm; "She
startled when I walked into the room" [syn:
jump,
start]