It's not good, but can be gripping (4)
I believe the answer is:
vice
'good but can be gripping' is the definition.
I can't tell whether this definition defines the answer.
'it's' is the wordplay.
I cannot really see how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
The remaining letters 'vic' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'not' is the link.
Can you help me to learn more?
(Other definitions for vice that I've seen before include "Wicked habit" , "Gripper - sin" , "venality?" , "Gripper - depravity" , "One that grips" .)