Free one for the French rugby player (6)
I believe the answer is:
unlock
'free' is the definition.
(thesaurus)
'one for the french rugby player' is the wordplay.
'one' becomes 'un' (I've seen this in other clues).
'for' means one lot of letters go next to another.
'the french rugby player' becomes 'lock' (I can't explain this - if you can you should give a lot more credence to this answer).
'un'+'lock'='UNLOCK'
Can you help me to learn more?
(Other definitions for unlock that I've seen before include "Crop" , "Release bolt" , "Open with key" , "Release with a key" .)