calumniatory

from WordNet (r) 3.0 (2006)

calumniatory
    adj 1: (used of statements) harmful and often untrue; tending to
           discredit or malign [syn: {calumniatory}, {calumnious},
           {defamatory}, {denigrative}, {denigrating},
           {denigratory}, {libellous}, {libelous}, {slanderous}]

from The Collaborative International Dictionary of English v.0.48

Calumniatory \Ca*lum"ni*a*to*ry\, a.
   Containing calumny; slanderous. --Montagu.
   [1913 Webster]