Contradiction for example accepted by people (8)
I believe the answer is:
negation
'contradiction' is the definition.
('negation' can be a synonym of 'contradiction')
'example accepted by people' is the wordplay.
'example' becomes 'eg'.
'accepted by' means one lot of letters goes inside another.
'people' becomes 'nation'.
'eg' inserted into 'nation' is 'NEGATION'.
'for' is the link.
(Other definitions for negation that I've seen before include "Disaffirmation" , "Contradiction" , "disagreement" , "Cancellation" , "Making denial" .)