Prisoner terribly inert, with deprivation no end (8)
I believe the answer is:
internee
'prisoner' is the definition.
(I know that internee is a type of prisoner)
'terribly inert with deprivation no end' is the wordplay.
I cannot really understand how this works, but
an anagram of 'inert' is 'inter' which is present in the answer.
'no' could be 'n' (common abbreviation) and 'n' is present in the answer.
The remaining letters 'ee' is a valid word 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 internee that I've seen before include "Alien confined in war" , "One kept prisoner" , "Suspect held" , "Prisoner of war living in armed camp or prison" , "One is held without trial" .)