The possibility of future success (8)
I believe the answer is:
prospect
'the possibility of future success' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for prospect that I've seen before include "Gray distantly associated with Eton College" , "likelihood of event taking place" , "Likely candidate" , "Outlook, visa" , "Extensive view; search for minerals" .)