Small mug (6)
'small mug' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for noggin that I've seen before include "Human head -- small drink" , "Head - tot" , "alcoholic drink?" , "Snifter" , "Small jug of 19, perhaps" .)
(Other definitions for cup that I've seen before include "Prize; vessel" , "Drinking bowl" , "Trophy; drinking vessel" , "Chalice; trophy" , "Container to drink from - prize" .)