Deprive of confidence (7)
I believe the answer is:
unnerve
'deprive of confidence' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for unnerve that I've seen before include "Cause to lose courage - even run away" , "spook" , "Deprive of confidence" , "scare" , "Disconcert, make ill at ease" .)