Heartless judge with a bad feeling of resentment (8)
I believe the answer is:
jealousy
'feeling of resentment' is the definition.
(jealousy is a resentful or bitter feeling)
'heartless judge with a bad' is the wordplay.
'heartless' means to remove the middle letters.
'with' means one lot of letters go next to another.
'bad' becomes 'lousy' (similar in meaning).
'judge' with its middle removed is 'je'.
'je'+'a'+'lousy'='JEALOUSY'
(Other definitions for jealousy that I've seen before include "Envious resentment" , "Suspicious resentment" , "bad emotion" , "Covetousness - envy" , "Feeling of envy" .)