Girl not wanting a financial backer (5)
'a financial backer' is the definition.
(I've seen this before)
'girl not wanting' is the wordplay.
'girl' becomes 'ange'.
'not wanting' becomes 'l' (I can't justify this - if you can you should believe this answer much more).
Can you help me to learn more?
(Other definitions for angel that I've seen before include "Guardian spirit; theatre investor", "Spiritual being - financial backer", "darling!", "Old coin; theatre investor", "somewhere on the Northern Line".)