Stop the French mismanagement (6)
I believe the answer is:
bungle
'mismanagement' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'stop the french' is the wordplay.
'stop' becomes 'bung' (bung is a kind of stop).
'the french' becomes 'le' ('the' in French).
'bung'+'le'='BUNGLE'
Can you help me to learn more?
(Other definitions for bungle that I've seen before include "[BEAR]" , "Do something carelessly or badly" , "(Make an) embarrassing mistake" , "Blunder" , "Botch, make a hames of" .)