She takes a month to get a 1st class return (5)
I believe the answer is:
maria
'she' is the definition.
'a month to get a 1st class return' is the wordplay.
'month' becomes 'M' (standard abbreviation).
'to get' means one lot of letters go next to another.
'a ast class' becomes 'air' (I am not sure about this - if you are sure you should believe this answer much more).
'return' says the letters should be written in reverse.
'a'+'m'='am'
'am' after 'air' is 'airam'.
'airam' reversed gives 'MARIA'.
'takes' is the link.
Can you help me to learn more?
(Other definitions for maria that I've seen before include "Italian Mary" , "Black --, -- Theresa" , "Lunar plains; girl's name" , "Black --, police van" , "(Of plant) become limp" .)