Idle investor makes a hash of representing pal (8,7)
I believe the answer is:
sleeping partner
'idle investor' is the definition.
(hands-off investor to a business)
'makes a hash of representing pal' is the wordplay.
'makes a hash of' is an anagram indicator.
'representing'+'pal'='representingpal'
'representingpal' with letters rearranged gives 'SLEEPING PARTNER'.
(Other definitions for sleeping partner that I've seen before include "A capital provider" , "silent in company?" , "Inactive business associate" , "One not known" .)