The Collaborative International Dictionary of English v.0.48:

Lewd \Lewd\ (l[=u]d), a. [Compar. Lewder (-[~e]r); superl.
   Lewdest.] [OE. lewed, lewd, lay, ignorant, vile, AS.
   l[=ae]wed laical, belonging to the laity.]
   1. Not clerical; laic; laical; hence, unlearned; simple.
      [Obs.]
      [1913 Webster]

            For if a priest be foul, on whom we trust,
            No wonder is a lewed man to rust.     --Chaucer.
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            So these great clerks their little wisdom show
            To mock the lewd, as learn'd in this as they. --Sir.
                                                  J. Davies.
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   2. Belonging to the lower classes, or the rabble; idle and
      lawless; bad; vicious. [Archaic] --Chaucer.
      [1913 Webster]

            But the Jews, which believed not, . . . took unto
            them certain lewd fellows of the baser sort, . . .
            and assaulted the house of Jason.     --Acts xvii.
                                                  5.
      [1913 Webster]

            Too lewd to work, and ready for any kind of
            mischief.                             --Southey.
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   3. Given to the promiscuous indulgence of lust; dissolute;
      lustful; libidinous. --Dryden.
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   4. Suiting, or proceeding from, lustfulness; involving
      unlawful sexual desire; as, lewd thoughts, conduct, or
      language.
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   Syn: Lustful; libidinous; licentious; profligate; dissolute;
        sensual; unchaste; impure; lascivious; lecherous;
        rakish; debauched. -- Lewd"ly, adv. -- Lewd"ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

lewdness
    n 1: the trait of behaving in an obscene manner [syn:
         obscenity, lewdness, bawdiness, salaciousness,
         salacity]

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "lewdness":
   Rabelaisianism, X-rated movie, animality, bawdiness, bawdry,
   blue movie, carnality, clitoromania, concupiscence, dirt,
   dirtiness, dirty movie, erotic art, erotic literature, eroticism,
   eroticomania, erotographomania, erotomania, fescenninity, filth,
   filthiness, fleshliness, foulness, furor uterinus, goatishness,
   gynecomania, horniness, hysteromania, iconolagny, lasciviousness,
   lecherousness, lechery, libidinousness, lickerishness,
   lubriciousness, lubricity, lust, lustfulness, nastiness,
   nymphomania, obscenity, offensiveness, pornographic art,
   pornographic literature, pornographomania, pornography, prurience,
   pruriency, randiness, ribaldry, salaciousness, salacity,
   satyriasis, satyrism, scurrility, sensuality, sexiness,
   sexploitation, sexuality, skin flick, smut, smuttiness,
   soft-core pornography, stag film, uteromania, vileness



Easton's 1897 Bible Dictionary:

Lewdness
   (Acts 18:14), villany or wickedness, not lewdness in the modern
   sense of the word. The word "lewd" is from the Saxon, and means
   properly "ignorant," "unlearned," and hence low, vicious (Acts
   17:5).