Compared to prison, it's splendid! (4)
I believe the answer is:
fine
'splendid' is the definition.
(I've seen this before)
'compared to prison 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 'fin' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for fine that I've seen before include "An exquisite penalty?" , "Sunny -- penalty" , "Fair - penalty" , "Excellent kind of monetary penalty" , "Acceptable - punishment" .)