That common, beastly lot? (4)
I believe the answer is:
herd
'that common' is the definition.
I can't tell whether this definition defines the answer.
'beastly lot?' is the wordplay.
'beastly' becomes 'her' (I can't explain this - if you can you should give a lot more credence to this answer).
'lot?' becomes 'd'.
'her'+'d'='HERD'
Can you help me to learn more?
(Other definitions for herd that I've seen before include "Group of animals of one kind" , "People in the mass" , "Bunch of cattle" , "Animal group" , "Group of, eg, cows" .)