He lacks expertise, not to mention something gripping (6)
I believe the answer is:
novice
'he lacks expertise not to mention something gripping' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he lacks expertise not' is the wordplay.
I cannot really understand how this works, but
'he' could be 'vic' (short for Victor) and 'vic' is present in the answer.
'not' could be 'no' (negative) and 'no' is found within the answer.
A single letter 'e' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for novice that I've seen before include "Probationary monk/nun" , "apprentice" , "Inexperienced learner" , "Rod, tee up the ship-worm" , "Beginner, perhaps at religious orders" .)