Teacup defect (4)
I believe the answer is:
chip
'teacup defect' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for chip that I've seen before include "Off the old block, he's junior" , "High ball" , "Sliver of wood or piece of potato" , "Counter used to represent money in games" , "Small piece of wood" .)