Narcissist's problem (3)
I believe the answer is:
ego
'narcissist's problem' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ego that I've seen before include "Aspect of the personality" , "Consciousness" , "Vowel to disappear, < say another" , "Inflated pride" , "One's image of oneself" .)