Finding it impossible to become famous (7)
I believe the answer is:
notable
'famous' is the definition.
('notable' can be a synonym of 'famous')
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for notable that I've seen before include "Striking" , "VIP" , "Remarkable, worthy of comment" , "Worthy of record" , "Great" .)