For a month, she has a first class return (5)
I believe the answer is:
maria
'for' is the definition.
Both the answer and definition are singular nouns.
Maybe you can see an association between them that I can't see?
'a month she has a first class return' is the wordplay.
'a month' becomes 'M' (standard abbreviation).
'she' becomes 'ra' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'has' says to put letters next to each other.
'a first class' becomes 'ai' (Ar - top quality).
'return' says the letters should be written in reverse.
'ra' put after 'ai' is 'aira'.
'aira' backwards is 'aria'.
'm'+'aria'='MARIA'
Can you help me to learn more?
(Other definitions for maria that I've seen before include "Ms Callas, soprano" , "Black --, police van" , "- Callas, twentieth century opera singer" , "More than one plain" , "one from West Side Story" .)