Merit of French wait (7)
I believe the answer is:
deserve
'merit' is the definition.
(I know that merit can be written as deserve)
'of french wait' is the wordplay.
'of french' becomes 'de' ('of' in French).
'wait' becomes 'serve' (to wait on someone is to serve them).
'de'+'serve'='DESERVE'
(Other definitions for deserve that I've seen before include "rate" , "Be entitled to" , "Severed (anag)" , "Be worth" , "Merit (something)" .)