Source : Webster's Revised Unabridged Dictionary (1913)

Immoral \Im*mor"al\, a. [Pref. im- not + moral: cf. F. immoral.]
   Not moral; inconsistent with rectitude, purity, or good
   morals; contrary to conscience or the divine law; wicked;
   unjust; dishonest; vicious; licentious; as, an immoral man;
   an immoral deed.

   Syn: Wicked; sinful; criminal; vicious; unjust; dishonest;
        depraved; impure; unchaste; profligate; dissolute;
        abandoned; licentious; lewd; obscene.

Source : WordNet®

immoral
     adj 1: violating principles of right and wrong [ant: {moral}, {amoral}]
     2: not adhering to ethical or moral principles; "base and
        unpatriotic motives"; "a base, degrading way of life";
        "cheating is dishonorable"; "they considered colonialism
        immoral"; "unethical practices in handling public funds"
        [syn: {base}, {dishonorable}, {dishonourable}, {unethical}]
     3: morally unprincipled; "immoral behavior"
     4: characterized by wickedness or immorality; "led a very bad
        life" [syn: {bad}]
     5: marked by immorality; deviating from what is considered
        right or proper or good; "depraved criminals"; "a
        perverted sense of loyalty"; "the reprobate conduct of a
        gambling aristocrat" [syn: {depraved}, {perverse}, {perverted},
         {reprobate}]