Easing of tensions between nations (7)
I believe the answer is:
detente
'easing of tensions between nations' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for detente that I've seen before include "Thaw in relations" , "peace during hostilities" , "Easing of international tension" , "The easing of tensions between nations" , "Easing of strained relationships between countries" .)