The Collaborative International Dictionary of English v.0.48:

doltish \dolt"ish\ (d[=o]lt"[i^]sh), a.
   Doltlike; dull in intellect; stupid; blockish; as, a doltish
   clown. -- Dolt"ish*ly, adv. -- Dolt"ish*ness, n.
   [1913 Webster]