Escape from aggressive Vader (5)
I believe the answer is:
evade
'escape' is the definition.
(I know that evade is a type of escape)
'from aggressive vader' is the wordplay.
'from' indicates a hidden word.
'EVADE' can be found hidden inside 'aggressive vader'.
(Other definitions for evade that I've seen before include "Dodge, stay clear of" , "skirt" , "Escape paying (tax)" , "Dodge, keep clear of" , "Dodge by cleverness or trickery" .)