Tail one wags in high spirits (7)
I believe the answer is:
elation
'high spirits' is the definition.
(synonyms)
'tail one wags' is the wordplay.
'tail one' anagrams to 'ELATION'.
However, I am unsure how the anagram is indicated.
'in' is the link.
Can you help me to learn more?
(Other definitions for elation that I've seen before include "Transport" , "exhibits successful pride" , "'High spirits, exhilaration (7)'" , "High feeling?" , "Exaltation" .)