A song about a subject a person can't stand (8)
I believe the answer is:
anathema
'subject a person can't stand' is the definition.
I can't tell whether this definition defines the answer.
'a song about a' is the wordplay.
'song' becomes 'anthem' (anthem is a kind of song).
'about' means one lot of letters goes inside another.
'a' inserted into 'anthem' is 'anathem'.
'anathem'+'a'='ANATHEMA'
Can you help me to learn more?
(Other definitions for anathema that I've seen before include "Something very greatly disliked" , "loathsome" , "Formal church curse of excommunication" , "Accursed by the Church" , "Execration" .)