Excited Greens die out (9)
I believe the answer is:
energised
'excited' is the definition.
('excited'->'energized' is in my internal thesaurus and 'ize'->'ise')
'greens die out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'greens'+'die'='greensdie'
'greensdie' anagrammed gives 'ENERGISED'.
(Other definitions for energised that I've seen before include "Gave vitality to" , "Roused" , "Animated" , "ready for action" , "Given drive" .)