Criminal bagging top-quality earthenware (7)
I believe the answer is:
faience
'earthenware' is the definition.
(I know that faience is a type of earthenware)
'criminal bagging top-quality' is the wordplay.
'criminal' becomes 'fence' (someone who handles stolen goods).
'bagging' means one lot of letters goes inside another (bag can mean to obtain or contain).
'top quality' becomes 'ai' (resembles A1, informal term for top quality).
'fence' placed around 'ai' is 'FAIENCE'.
(Other definitions for faience that I've seen before include "porcelain" , "A glazed earthenware" , "ceramic ware" .)