Discharge with hard shove (4)
I believe the answer is:
push
'shove' is the definition.
(I've seen this before)
'discharge with hard' is the wordplay.
'discharge' becomes 'pus' (discharge from the body).
'with' is a charade indicator (letters next to each other).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'pus'+'h'='PUSH'
(Other definitions for push that I've seen before include "Try to sell" , "Encourage" , "Offensive - press" , "Energy" , "See 8" .)