Grumble head of branch has put up charge (4)
I believe the answer is:
beef
'grumble' is the definition.
(both can mean to complain)
'head of branch has put up charge' is the wordplay.
'head of' indicates taking the first letters.
'has' says to put letters next to each other.
'put up' is a reversal indicator.
'charge' becomes 'fee' (fee is a kind of charge).
The initial letter of 'branch' is 'b'.
'fee' back-to-front is 'eef'.
'b'+'eef'='BEEF'
(Other definitions for beef that I've seen before include "Brawn; complaint" , "Grouse - meat" , "Grumble - muscle" , "gripe" , "Argument" .)