Discharge the man in spirit (5)
I believe the answer is:
rheum
'discharge' is the definition.
(I know that rheum is a type of discharge)
'man in spirit' is the wordplay.
'man' becomes 'he' (he refers to a man).
'in' indicates putting letters inside.
'spirit' becomes 'rum' (alcoholic spirit).
'he' put into 'rum' is 'RHEUM'.
'the' is the link.
(Other definitions for rheum that I've seen before include "sign of illness" , "Tears of a cold" , "Rhubarb genus; a head cold" , "Flowing water" , "Watery stuff" .)