Feeling sorry for number one infuriates tipsy elf (4-4)
I believe the answer is:
self-pity
'feeling' is the definition.
(I have seen 'ignoble feeling' mean 'self pity' so perhaps 'feeling' could also mean 'self pity')
'sorry for number one infuriates tipsy elf' is the wordplay.
'tipsy elf' can be anagrammed to 'SELF-PITY'.
However, I am not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for self-pity that I've seen before include "(Surgical) cut" , "Inwardly-directed compassion" , "Excessive unhappiness at one's lot" , "State of feeling sorry for one's own situation" , "Inward maudlin sorrow" .)