Letter or note written by devout holy man to the French (7)
I believe the answer is:
epistle
'letter' is the definition.
(I know that letter can be written as epistle)
'note written by devout holy man to the french' is the wordplay.
'note' becomes 'e' (musical note).
'written by' means one lot of letters go next to another.
'devout' becomes 'pi'.
'holy man' becomes 'st' (abbreviation for saint).
'to the french' becomes 'le' ('the' in French).
'e'+'pi'+'st'+'le'='EPISTLE'
'or' is the link.
(Other definitions for epistle that I've seen before include "A letter, biblical perhaps" , "(E.g. Paul's) letter" , "Pets lie (anag)" , "communication" , "Maybe Paul's" .)