The Collaborative International Dictionary of English v.0.48:

Bonnyclabber \Bon"ny*clab`ber\ (-kl[a^]b`b[~e]r), n. [Ir.
   bainne, baine, milk + clabar mud, mire.]
   Coagulated sour milk; loppered milk; curdled milk; --
   sometimes called simply clabber. --B. Jonson.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clabber \Clab"ber\, n. [See Bonnyclabber]
   Milk curdled so as to become thick.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clabber \Clab"ber\, v. i.
   To become clabber; to lopper.
   [1913 Webster]

WordNet (r) 3.0 (2006):

clabber
    n 1: raw milk that has soured and thickened
    v 1: turn into curds; "curdled milk" [syn: curdle, clabber,
         clot] [ant: homogenise, homogenize]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "clabber":
   Devonshire cream, albumen, batter, beat up, blood clot,
   bonnyclabber, butter, cake, casein, churn, clot, clotted cream,
   clump, cluster, coagulate, coagulum, colloid, colloidize, concrete,
   congeal, cornstarch, crassamentum, cream, curd, curdle, dough,
   egg white, embolus, emulsify, emulsionize, gaum, gel, gelatin,
   gelatinate, gelatinize, glair, glop, glue, gluten, goo, gook, goop,
   gruel, grume, gumbo, gunk, incrassate, inspissate, jam, jell,
   jellify, jelly, knot, legumin, loblolly, lopper, loppered milk,
   lump, molasses, mucilage, mucus, pap, paracasein, paste, porridge,
   pudding, pulp, puree, putty, rob, semifluid, semiliquid, set, size,
   soup, starch, sticky mess, syrup, thick, thicken, thrombus,
   treacle, turn, whip