Clothes the French make incomprehensible (6)
I believe the answer is:
garble
'make incomprehensible' is the definition.
I can't judge whether this defines the answer.
'clothes the french' is the wordplay.
'clothes' becomes 'garb' (garb is a kind of clothes).
'the french' becomes 'le' ('the' in French).
'garb'+'le'='GARBLE'
Can you help me to learn more?
(Other definitions for garble that I've seen before include "jumble" , "Indistinct speech" , "Distort text or its meaning" , "Confuse (a message)" , "distorted transmission" .)