Remarkable theory won't, when revised (10)
I believe the answer is:
noteworthy
'remarkable' is the definition.
('noteworthy' can be a synonym of 'remarkable')
'theory won't when revised' is the wordplay.
'when revised' indicates an anagram (I've seen this in other clues).
'theory'+'wont'='theorywont'
'theorywont' anagrammed gives 'NOTEWORTHY'.
(Other definitions for noteworthy that I've seen before include "important" , "Signal" , "Interesting, significant" , "Of significance" .)