The Collaborative International Dictionary of English v.0.48:

Kibosh \Ki"bosh\, n.
   1. Nonsense; stuff; also, fashion; style. [Slang]
      [Webster 1913 Suppl.]

   2. Portland cement when thrown or blown into the recesses of
      carved stonework to intensify the shadows.

   To put the kibosh on, to dispose of; to squelch; to
      terminate; put an end to; to do for. [Slang]
      [Webster 1913 Suppl. +PJC]

WordNet (r) 3.0 (2006):

kibosh
    v 1: stop from happening or developing; "Block his election";
         "Halt the process" [syn: stop, halt, block, kibosh]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "kibosh":
   KO, bugger, call off, cancel, complete, cripple, de-energize,
   debilitate, delete, disable, disenable, dispose of, drain,
   drop the curtain, end off, enfeeble, expunge, extinguish, finalize,
   finish, fold up, get it over, get over with, get through with,
   give the quietus, hamstring, hors de combat, inactivate,
   incapacitate, kayo, kill, knock out, lame, maim, perfect,
   polish off, put, put paid to, queer, queer the works, sabotage,
   scrag, shoot down, spike, unfit, weaken, wing, wipe out, wreck,
   zap