The Collaborative International Dictionary of English v.0.48:

Damnatory \Dam"na*to*ry\ (d[a^]m"n[.a]*t[-o]*r[y^]), a. [L.
   damnatorius, fr. damnator a condemner.]
   Dooming to damnation; condemnatory. "Damnatory invectives."
   --Hallam.
   [1913 Webster]

WordNet (r) 3.0 (2006):

damnatory
    adj 1: threatening with damnation [syn: damnatory, damning]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "damnatory":
   Rabelaisian, abusive, blackening, blameful, blasphemous,
   calumniatory, calumnious, censorious, comminatory, condemnatory,
   contemptuous, contumelious, cursing, denunciatory, deprecative,
   deprecatory, depreciative, derisive, dirty, disparaging,
   dysphemistic, epithetic, excommunicative, excommunicatory,
   execrating, execrative, execratory, foul, fulminatory, imprecatory,
   invective, inveighing, judgmental, maledictory, objurgatory,
   obscene, priggish, profane, proscriptive, raw, reproachful,
   reprobative, reviling, ribald, ridiculing, risque, scatologic,
   scoffing, scurrile, scurrilous, vile, vilifying, vituperative