Aged holy man singularly accommodating to Billy Bunter (4,5)
I believe the answer is:
grey friar
'billy bunter' is the definition.
The definition suggests a singular noun which matches the answer.
'aged holy man singularly accommodating' is the wordplay.
I cannot quite understand how this works, but
'man' could be 'friar' (I have seen 'Religious man ' mean 'friar' so perhaps 'man' could also mean 'friar') and 'friar' is present in the answer.
The remaining letters 'grey' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Another definition for grey friar that I've seen is " Franciscan".)