Card file I rearranged and cleared up (9)
I believe the answer is:
clarified
'cleared up' is the definition.
('clarify' can be a synonym of 'clear up')
'card file i rearranged' is the wordplay.
'rearranged' indicates an anagram.
'card'+'file'+'i'='cardfilei'
'cardfilei' is an anagram of 'CLARIFIED'.
'and' is the link.
(Other definitions for clarified that I've seen before include "Explained - made transparent" , "Elucidated" .)