The Collaborative International Dictionary of English v.0.48:

Lambaste \Lam*baste"\, v. t. [Lam + baste to beat.]
   To beat severely; specifically, to beat with a cane. [Low]
   --Nares.

   Syn: cane, flog, lambaste.
        [1913 Webster + WordNet 1.5]

   2. to scold, reprimand, or berate harshly.

   Syn: rebuke, rag, reproof, reprimand, jaw, dress down, scold,
        chide, berate, bawl out, jaw at, remonstrate with, chew
        out, chew up, have words with, lambast.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

lambaste
    v 1: beat with a cane [syn: cane, flog, lambaste,
         lambast]
    2: censure severely or angrily; "The mother scolded the child
       for entering a stranger's car"; "The deputy ragged the Prime
       Minister"; "The customer dressed down the waiter for bringing
       cold soup" [syn: call on the carpet, take to task,
       rebuke, rag, trounce, reproof, lecture,
       reprimand, jaw, dress down, call down, scold,
       chide, berate, bawl out, remonstrate, chew out,
       chew up, have words, lambaste, lambast]

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "lambaste":
   admonish, attack, bang, baste, batter, bawl out, beat,
   beat all hollow, beat hollow, belabor, berate, best, birch,
   blister, bludgeon, buffet, call down, cane, castigate, censure,
   chew, chew ass, chew out, chide, clobber, crawl, cudgel, cuss out,
   defeat, destroy, do in, dress down, drub, excoriate, fix, flail,
   flap, flay, flog, give a going-over, give hail Columbia, give hell,
   give the deuce, give what-for, hammer, hide, hors de combat,
   horsewhip, jack up, knock, larrup, lash, lather, lick, maul,
   outclass, outdo, outfight, outgeneral, outmaneuver, outpoint,
   outrun, outsail, outshine, paste, patter, pelt, pommel, pound,
   pulverize, pummel, put, rap, ream, ream ass, ream out, rebuke,
   reprimand, reprove, revile, ruin, scold, scourge, settle, shellac,
   sit on, skin, skin alive, sledgehammer, smear, smother, spank,
   thrash, thresh, thump, trim, triumph over, trounce, undo, upbraid,
   wallop, whip, worst