Say State accepts denial (8)
I believe the answer is:
negation
'denial' is the definition.
(negation is a kind of denial)
'say state accepts' is the wordplay.
'say' becomes 'eg'.
'state' becomes 'nation' (synonyms).
'accepts' means one lot of letters goes inside another.
'eg' placed into 'nation' is 'NEGATION'.
(Other definitions for negation that I've seen before include "opposite" , "disagreement" , "Disaffirmation" , "Making denial" , "Contradiction" .)