Dextrous trainee included pottery (5)
I believe the answer is:
delft
'pottery' is the definition.
(I've seen this before)
'dextrous trainee included' is the wordplay.
'dextrous' becomes 'deft' ('deft' can be a synonym of 'dextrous').
'trainee' becomes 'l'.
'included' is an insertion indicator.
'deft' going around 'l' is 'DELFT'.
(Other definitions for delft that I've seen before include "City in the Netherlands" , "Dutch blue and white glazed earthenware" , "type of pottery" , "Blue and white earthenware (from Holland)" , "Dutch blue and white ware" .)