Droop with immediate loss thus initially (4)
I believe the answer is:
wilt
'droop' is the definition.
('wilt' can be a synonym of 'droop')
'with immediate loss thus initially' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'with immediate loss thus' is 'WILT'.
(Other definitions for wilt that I've seen before include "lose energy?" , "Droop in the heat" , "Become flaccid" , "Flag" , "Decline" .)