Source : Webster's Revised Unabridged Dictionary (1913)

Immodest \Im*mod"est\, a. [F. immodeste, L. immodestus
   immoderate; pref. im- not + modestus modest. See {Modest}.]
   1. Not limited to due bounds; immoderate.

   2. Not modest; wanting in the reserve or restraint which
      decorum and decency require; indecent; indelicate;
      obscene; lewd; as, immodest persons, behavior, words,
      pictures, etc.

            Immodest deeds you hinder to be wrought, But we
            proscribe the least immodest thought. --Dryden.

   Syn: Indecorous; indelicate; shameless; shameful; impudent;
        indecent; impure; unchaste; lewd; obscene.

Source : WordNet®

immodest
     adj 1: having or showing an exaggerated opinion of your importance,
            ability, etc; "brash immodest boasting" [ant: {modest}]
     2: offending against sexual mores in conduct or appearance
        [ant: {modest}]