Composed a French female a final letter (7)
I believe the answer is:
unfazed
'composed' is the definition.
(both can mean calm)
'a french female a final letter' is the wordplay.
'a french' becomes 'un' ('a' in French).
'female' becomes 'f' (abbreviation).
'final letter' becomes 'zed'.
'un'+'f'+'a'+'zed'='UNFAZED'
(Other definitions for unfazed that I've seen before include "not bothered" , "Unperturbed" , "Not disconcerted" .)