Relaxation in wigwam with river all around (7)
I believe the answer is:
detente
'relaxation' is the definition.
(a detente is a relaxation of hostile relations)
'wigwam with river all around' is the wordplay.
'wigwam with' becomes 'tent' (I can't justify this - if you can you should believe this answer much more).
'river' becomes 'dee' (River Dee).
'all around' means one lot of letters goes inside another.
'tent' going into 'dee' is 'DETENTE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for detente that I've seen before include "The easing of tensions between nations" , "Easing of hostility between countries" , "Thaw in relations" , "Easing of strained relationships between countries" , "peace during hostilities" .)