Discharge soldier, initially on bench (4)
I believe the answer is:
spew
'discharge' is the definition.
(I know that spew is a more specific form of the action cough out)
'soldier initially on bench' is the wordplay.
'initially' says to take the initial letters.
'on' says to put letters next to each other.
'bench' becomes 'pew' (pew is a kind of bench).
The first letter of 'soldier' is 's'.
's'+'pew'='SPEW'
(Other definitions for spew that I've seen before include "Fetch up" , "Erupt, eject" , "Casst out in a stream" , "Belch forth" , "Vomit (colloq.)" .)