Not well, start feeling appeal leader has me in disfavour (7)

'disfavour' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'not well start feeling appeal leader has me' is the wordplay.
'not well' becomes 'ill' ('ill' is the opposite to 'well').
'start' suggests taking the first letters.
'leader' suggests taking the first letters.
'has' means one lot of letters go next to another.
The first letter of 'feeling' is 'f'.
The first letter of 'appeal' is 'a'.
'ill'+'f'+'a'+'me'='ILLFAME'

'in' is the link.

Can you help me to learn more?