Half discouraged about decade in diplomatic activity (7)
I believe the answer is:
detente
'diplomatic activity' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'half discouraged about decade in' is the wordplay.
'half' suggests halving the letters.
'discouraged' becomes 'deterred' ('deter' can be a synonym of 'discourage').
'about decade' becomes 'ten' (synonyms. I am not sure about the 'about' bit.).
'in' means one lot of letters goes inside another.
'deterred' halved is 'dete'.
'dete' going around 'ten' is 'DETENTE'.
Can you help me to learn more?
(Other definitions for detente that I've seen before include "Improvement of political relations" , "peace during hostilities" , "The easing of tensions between nations" , "Easing of international tension" , "Easing of international hostility" .)