That man in drink gets discharge (5)
I believe the answer is:
rheum
'discharge' is the definition.
(thesaurus)
'that man in drink' is the wordplay.
'that man' becomes 'he'.
'in' is an insertion indicator.
'drink' becomes 'rum' (rum is a kind of drink).
'he' put into 'rum' is 'RHEUM'.
'gets' acts as a link.
(Other definitions for rheum that I've seen before include "Tears of a cold" , "cold once upon a time" , "Watery fluid" , "nasal discharge" , "Poetic tears" .)