Dog with acceptable meat (6)
I believe the answer is:
mutton
'meat' is the definition.
(mutton is a kind of meat)
'dog with acceptable' is the wordplay.
'dog' becomes 'mutt' (mutt is a kind of dog).
'with' means one lot of letters go next to another.
'acceptable' becomes 'on' (as opposed to not on, unacceptable).
'mutt'+'on'='MUTTON'
(Other definitions for mutton that I've seen before include "Flesh of sheep" , "Meat from sheep" , "Sheep's flesh" , "Meat that may be dressed as lamb" , "Sheep as food" .)