Isn't fame ridiculously obvious? (8)
I believe the answer is:
manifest
'obvious?' is the definition.
('manifest' can be similar in meaning to 'obvious')
'isn't fame ridiculously' is the wordplay.
'ridiculously' indicates an anagram.
'isnt'+'fame'='isntfame'
'isntfame' is an anagram of 'MANIFEST'.
(Other definitions for manifest that I've seen before include "Plain - cargo list" , "Cargo list - it's quite clear" , "(Of ghost) appear" , "list of passengers flying" , "Reveal" .)