Mongrel will get no flipping meat (6)
I believe the answer is:
mutton
'meat' is the definition.
(mutton is a kind of meat)
'mongrel will get no flipping' is the wordplay.
'mongrel' becomes 'mutt' ('mutt' can be a synonym of 'mongrel').
'will get' is a charade indicator (letters next to each other).
'flipping' says the letters should be written backwards.
'no' back-to-front is 'on'.
'mutt'+'on'='MUTTON'
(Other definitions for mutton that I've seen before include "Meat that may dress as lamb" , "Sheep's flesh" , "Meat that may be dressed as lamb" , "Meat sometimes dressed as lamb" , "Dead, we are told" .)