Declare why make money for long (5)
I believe the answer is:
yearn
'long' is the definition.
(synonyms)
'declare why make money' is the wordplay.
'declare' shows a homophone (sound like).
'make money' becomes 'earn' (I've seen this before).
'why' sounds like 'y'.
'y'+'earn'='YEARN'
'for' is the link.
(Other definitions for yearn that I've seen before include "Hanker" , "Desire strongly" , "Have strong desire" , "Long - pine" , "Pant - pine" .)