Punishment one really feels (4)
I believe the answer is:
pain
'punishment' is the definition.
(thesaurus)
'one really feels' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
The remaining letters 'pan' 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 pain that I've seen before include "Sensation of hurt" , "Physical discomfort" , "Agony" , "Suffering, ache" , "Suffering, distress" .)