Knight meets a French religious lady (3)
I believe the answer is:
nun
'religious lady' is the definition.
(I've seen this before)
'knight meets a french' is the wordplay.
'knight' becomes 'n' (chess).
'meets' is a charade indicator (letters next to each other).
'a french' becomes 'un' ('a' in French).
'n'+'un'='NUN'
(Other definitions for nun that I've seen before include "Fancy pigeon variety" , "A palindromic lady in religious order" , "Woman in religious order" , "One in holy order" , "Member of convent" .)