Mug in set gets smashed (5)
I believe the answer is:
stein
'mug' is the definition.
(stein is a kind of mug)
'in set gets smashed' is the wordplay.
'gets smashed' indicates anagramming the letters (the original order of letters is smashed up).
'in'+'set'='inset'
'inset' with letters rearranged gives 'STEIN'.
(Other definitions for stein that I've seen before include "Gertrude ---; US writer" , "Gertrude __, avant-garde US author, d. 1946" , "German tankard" , "Glass" , "Earthenware beer jug" .)