The effrontery to make money .... (5)
I believe the answer is:
brass
This clue is a double definition.
'the effrontery' is the first definition.
(synonyms)
'money' is the second definition.
(brass can informally mean money)
'to make' is the link.
(Other definitions for brass that I've seen before include "Alloy of Cu and Zn" , "Alloy of copper and zinc" , "An alloy; part of orchestra" , "some musicians!" , "Metal alloy" .)