High anxiety (5)
I believe the answer is:
angst
'high anxiety' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for angst that I've seen before include "uneasiness" , "Gnats (anag.)" , "Acute, but unspecific, feeling of anxiety" , "Nagging worry" , "Terrible butterflies" .)