Loutish (6)
I believe the answer is:
oafish
'loutish' is the definition.
(synonyms)
This is all the clue.
(Other definitions for oafish that I've seen before include "Like a lout" , "Uncouth" , "In the manner of a clumsy and stupid person" , "Like a boorish person" , "Boorish, clumsy" .)