Feeling of apprehension (5)
I believe the answer is:
angst
'feeling of apprehension' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for angst that I've seen before include "Stang (anag)" , "Feeling of anxiety or guilt" , "Horrible feeling" , "Nagging worry" , "Great anxiety" .)