Beastly little sister carrying bag back from beach (7)
I believe the answer is:
swinish
'beastly' is the definition.
(I've seen this before)
'little sister carrying bag back from beach' is the wordplay.
I cannot quite understand how this works, but
'from' could be 'in' (I've seen this in other clues) and 'in' is present in the answer.
The remaining letters 'swish' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for swinish that I've seen before include "Porcine" , "Beastly" , "like Eumaeus's charges" , "Piglike" , "Like a cad" .)