Back home in the country after onset of intense exhaustion (9)
I believe the answer is:
inanition
'exhaustion' is the definition.
(I know that inanition is a type of exhaustion)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for inanition that I've seen before include "lack of enthusiasm" , "being exhausted" , "Exhaustion" , "Lack of vigour" , "Lassitude" .)