Source : Webster's Revised Unabridged Dictionary (1913)

Unholy \Un*ho"ly\, a.
   Not holy; unhallowed; not consecrated; hence, profane;
   wicked; impious. -- {Un*ho"li*ly}, adv. -- {Un*ho"li*ness},
   n.

Source : WordNet®

unholy
     adj 1: not hallowed or consecrated [syn: {unhallowed}] [ant: {holy}]
     2: extremely evil or cruel; expressive of cruelty or befitting
        hell; "something demonic in him--something that could be
        cruel"; "fires lit up a diabolic scene"; "diabolical
        sorcerers under the influence of devils"; "a fiendish
        despot"; "hellish torture"; "infernal instruments of war";
        "satanic cruelty"; "unholy grimaces" [syn: {demonic}, {diabolic},
         {diabolical}, {fiendish}, {hellish}, {infernal}, {satanic}]
     3: having committed unrighteous acts; "a sinful person" [syn: {sinful},
         {wicked}]
     [also: {unholiest}, {unholier}]