Expressing refusal, say, to enter local (8)
I believe the answer is:
negative
'expressing refusal' is the definition.
('no' is answering in the negative)
'say to enter local' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'to enter' is an insertion indicator.
'local' becomes 'native' (similar in meaning).
'eg' inserted within 'native' is 'NEGATIVE'.
(Other definitions for negative that I've seen before include "thumbs down" , "This required for development" , "The photographic film expresses refusal" , "Less than positive" , "Opposite of affirmative" .)