The Collaborative International Dictionary of English v.0.48:

Lumpy \Lump"y\, a. [Compar. Lumpier; superl. Lumpiest.]
   Full of lumps, or small compact masses; as, a lumpy bed; a
   lumpy batch of dough.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lumpy
    adj 1: like or containing small sticky lumps; "the dumplings
           were chunky pieces of uncooked dough" [syn: chunky,
           lumpy]
    2: having lumps; not smooth and even in texture; "lumpy gravy"

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "lumpy":
   awkward, bulky, bumpy, caked, cakey, chunky, clabbered, clotted,
   clumsy, coagulated, congealed, crude, cumbersome, cumbrous, curded,
   curdled, elephantine, gelatinized, gnarled, gnarly, grainy,
   granular, grumous, hulking, hulky, incrassate, inspissate,
   inspissated, jelled, jellied, knobbly, knobby, knotted, knotty,
   knurled, knurly, lubberly, lumbering, lumpish, massive, massy,
   nodose, nodular, ponderous, raw, rough, roughhewn, rude, studded,
   thickened, undressed, uneven, unfashioned, unfinished, unformed,
   unpolished, unwieldy