Even in action, dispirited (8)
I believe the answer is:
deflated
'dispirited' is the definition.
(I know that deflated is a more specific form of the attribute dispirited)
'even in action' is the wordplay.
'even' becomes 'flat' (similar in meaning).
'in' means one lot of letters goes inside another.
'action' becomes 'deed' (deed is a kind of action).
'flat' inserted into 'deed' is 'DEFLATED'.
(Other definitions for deflated that I've seen before include "Crestfallen" , "Collapsed by releasing air" , "Collapsed due to release of gas" , "Put down" , "Let out air or gas from" .)