Disreputable loud chef tails off (6)
I believe the answer is:
'disreputable' is the definition.
(similar in meaning)
I cannot understand how the rest of the clue works.
(Other definitions for louche that I've seen before include "Ignominious" , "Shifty or disreputable" , "Shasy or questionable, from France" , "Appealingly disreputable" , "Seedy" .)