Ambassador in wild party gets treatment (7)
I believe the answer is:
therapy
'treatment' is the definition.
(I know that treatment can be written as therapy)
'ambassador in wild party' is the wordplay.
'ambassador' becomes 'he' (His or Her Excellency).
'in' is an insertion indicator.
'wild' is an anagram indicator.
'party' anagrammed gives 'trapy'.
'he' going into 'trapy' is 'THERAPY'.
'gets' is the link.
(Other definitions for therapy that I've seen before include "will do you good" , "Relieving treatment" , "Curative treatment" , "Medical treatment" , "Healing treatment" .)