Startle when a vehicle is caught in a strong wind (9)
I believe the answer is:
galvanise
'startle' is the definition.
(I know that startle can be written as galvanise)
'a vehicle is caught in a strong wind' is the wordplay.
'a vehicle' becomes 'van' (van is a kind of vehicle).
'caught in' indicates putting letters inside.
'a strong wind' becomes 'gale' (I've seen this before).
'van'+'is'='vanis'
'vanis' going inside 'gale' is 'GALVANISE'.
'when' is the link.
(Other definitions for galvanise that I've seen before include "subject to action of electric current" , "Electrify" , "Excite" .)