Wear down a supporter of French (6)
I believe the answer is:
abrade
'wear down' is the definition.
(thesaurus)
'a supporter of french' is the wordplay.
'supporter' becomes 'bra' (I've seen this before).
'of french' becomes 'de'.
'a'+'bra'+'de'='ABRADE'
(Other definitions for abrade that I've seen before include "Rub off or scrape away" , "A beard (anag.)" , "Wear away by erosion" , "Scrape away, erode" , "Wear away by rubbing, scrape" .)