Endless good fortune concerning money (5)
I believe the answer is:
lucre
'money' is the definition.
(lucre is a kind of money)
'endless good fortune concerning' is the wordplay.
'endless' means to remove the last letter.
'good fortune' becomes 'luck' (I've seen this before).
'concerning' becomes 're'.
'luck' with its last letter taken off is 'luc'.
'luc'+'re'='LUCRE'
(Other definitions for lucre that I've seen before include "financial gain" , "monetary gain" , "benefits from crime" , "(Dishonourably gained) money (poetic, literary)" , "Ill-gotten riches" .)