The girl who raised me before mother? (4)
I believe the answer is:
emma
'the girl' is the definition.
'raised me before mother?' is the wordplay.
'raised' says the letters should be written in reverse.
'before' means one lot of letters go next to another.
'mother?' becomes 'ma' (ma is a kind of mother).
'me' in reverse letter order is 'em'.
'em'+'ma'='EMMA'
'who' acts as a link.
(Other definitions for emma that I've seen before include "It's a girl - ask me ma" , "Jane Austen work - Ms Bunton, former Baby Spice" , "Madame Bovary, perhaps" , "Lady - Hamilton, Nelson-s mistress" , "Mrs Bovary" .)