Cheerful after injury is concluded (5,2)
I believe the answer is:
wound up
'is concluded' is the definition.
(thesaurus)
'cheerful after injury' is the wordplay.
'cheerful' becomes 'up' (I've seen this in other clues).
'after' is a charade indicator (letters next to each other).
'injury' becomes 'wound' (wound is a kind of injury**).
'up' after 'wound' is 'WOUND-UP'.
(Other definitions for wound up that I've seen before include "being put into liquidation" , "Angry" , "highly irritated" , "Overwrought" , "Teased" .)