Every now and then Joe has awful feelings of resentment towards a rival (8)
I believe the answer is:
jealousy
'feelings of resentment towards a rival' is the definition.
I can't judge whether this definition defines the answer.
'every now and then joe has awful' is the wordplay.
'every now and then' indicates alternate letters (letters selected at regular intervals).
'awful' becomes 'lousy' (I've seen this in another clue).
'joe'+'has'='joehas'
The alternate letters of 'joehas' are 'jea'.
'jea'+'lousy'='JEALOUSY'
Can you help me to learn more?
(Other definitions for jealousy that I've seen before include "Envious emotion" , "bad emotion" , "Envious resentment" , "It is called the green-eyed monster" , "Feeling of envy" .)