[1] : The Collaborative International Dictionary of English v.0.48

immoral \immor"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.
        1913 webster

[2] : WordNet (r) 2.0

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
see also:
moral amoral base dishonorable dishonourable unethical 
bad depraved perverse perverted reprobate 

[3] : Moby Thesaurus II by Grady Ward, 1.0

89 moby thesaurus words for "immoral":
   abandoned, amoral, bad, base, carnal, concupiscent, conscienceless,
   corrupt, corrupted, criminal, crooked, dark, debauched, degenerate,
   depraved, devious, dirty, dishonest, dishonorable, dissolute,
   doubtful, dubious, evasive, evil, felonious, filthy, fishy,
   flagitious, fraudulent, ill-got, ill-gotten, immodest, impure,
   indecent, indirect, iniquitous, insidious, lascivious, lecherous,
   lewd, libertine, libidinous, licentious, lustful, nefarious,
   nonmoral, not kosher, obscene, pornographic, questionable,
   reprobate, rotten, salacious, shady, shameless, shifty, sinful,
   sinister, slippery, smutty, steeped in vice, suspicious,
   treacherous, tricky, unchaste, unclean, uncleanly, unconscienced,
   unconscientious, unconscionable, underhand, underhanded, unethical,
   unmoral, unprincipled, unregenerate, unsavory, unscrupulous,
   unstraightforward, vice-laden, vice-prone, vicious, vile,
   villainous, wanton, wicked, without remorse, without shame,
   wrong

[4] : THE DEVIL'S DICTIONARY ((C)1911 Released April 15 1993)

immoral, adj.  inexpedient.  whatever in the long run and with regard
to the greater number of instances men find to be generally
inexpedient comes to be considered wrong, wicked, immoral.  if man's
notions of right and wrong have any other basis than this of
expediency; if they originated, or could have originated, in any other
way; if actions have in themselves a moral character apart from, and
nowise dependent on, their consequences -- then all philosophy is a
lie and reason a disorder of the mind.

Immoral >> I Words
Immoral, definition of term: Immoral
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