Isolation of a country admitting deception (10)
I believe the answer is:
alienation
'isolation' is the definition.
(alienation is a kind of isolation)
'a country admitting deception' is the wordplay.
'country' becomes 'nation' ('nation' can be a synonym of 'country'**).
'admitting' indicates putting letters inside.
'deception' becomes 'lie' (I've seen this in other clues).
'a'+'nation'='anation'
'anation' enclosing 'lie' is 'ALIENATION'.
'of' is the link.
(Other definitions for alienation that I've seen before include "Disunity" , "Estrangement" , "State of feeling isolated" , "Brecht's effect" , "Isolation" .)