Disquietude (6)
I believe the answer is:
unease
'disquietude' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for unease that I've seen before include "State of worry and lack of confidence" , "Anxiety, discontent" , "Disquiet" , "State of anxiety" , "Discomfort or apprehension" .)