The Collaborative International Dictionary of English v.0.48:

Cloddish \Clod"dish\, a.
   Resembling clods; gross; low; stupid; boorish. --Hawthorne.
   -- Clod"dish*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cloddish
    adj 1: heavy and dull and stupid [syn: cloddish, doltish]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "cloddish":
   Boeotian, asinine, beef-brained, beef-witted, blockish, boorish,
   bovine, carlish, chumpish, churlish, clodhopping, clownish,
   countrified, country-born, country-bred, cowish, crass, dense,
   doltish, dullard, dumb, duncical, duncish, farmerish, fat,
   from the sticks, gross, hayseed, hick, hicky, hobnailed,
   hooliganish, ill-bred, ineducable, inurbane, klutzy, loobyish,
   loutish, lubberly, lumpen, lumpish, oafish, opaque, raffish,
   roughneck, rowdy, rowdyish, rube, ruffianly, sottish, stupid,
   thick, uncivilized, uncouth, uncultivated, uncultured, unpolished,
   unrefined, unteachable, up-country, wrongheaded, yokel, yokelish