A French match is separate (5)
I believe the answer is:
untie
'is separate' is the definition.
(I've seen this before)
'a french match' is the wordplay.
'a french' becomes 'un' ('a' in French).
'match' becomes 'tie' (I've seen this before).
'un'+'tie'='UNTIE'
(Other definitions for untie that I've seen before include "Loosen ropes or knots" , "Free from binds" , "Loosen, as laces" , "resolve" , "Free from restraining bonds or ropes" .)