Oktoberfest mug (5)
I believe the answer is:
stein
'oktoberfest mug' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for stein that I've seen before include "German tankard" , "Inset (anag.)" , "Earthenware beer jug" , "Gertrude __, avant-garde US author, d. 1946" , "Inset into earthenware mug for beer" .)