Statement's obscure about rough cut (6)
I believe the answer is:
dictum
'statement's' is the definition.
(dictum is a kind of statement)
'obscure about rough cut' is the wordplay.
'obscure' becomes 'dim' (both can mean dark).
'about' indicates putting letters inside.
'rough' indicates an anagram (a rough or broken ordering of the letters).
'cut' with letters rearranged gives 'ctu'.
'dim' placed around 'ctu' is 'DICTUM'.
(Other definitions for dictum that I've seen before include "Authoritative declaration" , "Utterance" , "A Latin saying or formal expression of opinion" , "Saw" , "Decree; maxim" .)