Not promising money after they turned up (from Calais, that is) (4)
I believe the answer is:
slim
'not promising' is the definition.
(as in slim chances)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for slim that I've seen before include "Lean" , "insufficient" , "Very small; WW2 Burma commander" , "Take off weight as by dieting" , "without much body" .)