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 judge 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 located in the answer.
The remaining letters 'vic' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'not' acts as a 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" .)