The Collaborative International Dictionary of English v.0.48:

Unhallowed \Un*hal"lowed\, a. [Pref. un- not + hallowed.]
   Not consecrated; hence, profane; unholy; impious; wicked.
   [1913 Webster]

         In the cause of truth, no unhallowed violence . . . is
         either necessary or admissible.          --E. D.
                                                  Griffin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unhallowed
    adj 1: not hallowed or consecrated [syn: unholy, unhallowed]
           [ant: holy]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "unhallowed":
   demoniac, demonic, devilish, diabolic, fleshly, irreverent,
   mundane, nonsacred, profane, reprobate, satanic, secular,
   serpentine, temporal, unblessed, ungodly, unholy, unregenerate,
   unsacred, unsanctified, worldly