The Collaborative International Dictionary of English v.0.48:

Looby \Loo"by\, n.; pl. Loobies. [Cf. Lob.]
   An awkward, clumsy fellow; a lubber. --Swift.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "looby":
   Babbitt, Boeotian, Philistine, arriviste, block, blockhead,
   blunderer, blunderhead, boor, botcher, bounder, bourgeois, bucolic,
   bumbler, bumpkin, bungler, cad, churl, clod, clodhopper,
   clodknocker, clot, clown, country bumpkin, dimwit, dolt, donkey,
   dope, dullard, dumb cluck, dumbbell, dummy, dunce, epicier, farmer,
   fumbler, gawk, gowk, groundling, guttersnipe, hayseed, hick,
   hillbilly, hooligan, ill-bred fellow, jobbernowl, klutz, lackwit,
   lamebrain, lightweight, lobster, loon, lout, low fellow, lubber,
   lug, lummox, lump, mucker, niais, nincompoop, ninny, ninnyhammer,
   nitwit, noddy, nouveau riche, oaf, ox, palooka, parvenu, peasant,
   put, ribald, rough, roughneck, rowdy, rube, ruffian, rustic,
   slouch, slubberer, stupid, thickwit, upstart, vulgarian, vulgarist,
   witling, yokel