The Collaborative International Dictionary of English v.0.48:

Vulgar \Vul"gar\, a. [L. vulgaris, from vulgus the multitude,
   the common people; of uncertain origin: cf. F. vulgaire. Cf.
   Divulge.]
   [1913 Webster]
   1. Of or pertaining to the mass, or multitude, of people;
      common; general; ordinary; public; hence, in general use;
      vernacular. "As common as any the most vulgar thing to
      sense. " -- Shak.
      [1913 Webster]

            Things vulgar, and well-weighed, scarce worth the
            praise.                               --Milton.
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            It might be more useful to the English reader . . .
            to write in our vulgar language.      --Bp. Fell.
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            The mechanical process of multiplying books had
            brought the New Testament in the vulgar tongue
            within the reach of every class.      --Bancroft.
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   2. Belonging or relating to the common people, as
      distinguished from the cultivated or educated; pertaining
      to common life; plebeian; not select or distinguished;
      hence, sometimes, of little or no value. "Like the vulgar
      sort of market men." --Shak.
      [1913 Webster]

            Men who have passed all their time in low and vulgar
            life.                                 --Addison.
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            In reading an account of a battle, we follow the
            hero with our whole attention, but seldom reflect on
            the
            vulgar heaps of slaughter.            --Rambler.
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   3. Hence, lacking cultivation or refinement; rustic; boorish;
      also, offensive to good taste or refined feelings; low;
      coarse; mean; base; as, vulgar men, minds, language, or
      manners.
      [1913 Webster]

            Be thou familiar, but by no means vulgar. --Shak.
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   Vulgar fraction. (Arith.) See under Fraction.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Vulgar \Vul"gar\, n. [Cf. F. vulgaire.]
   [1913 Webster]
   1. One of the common people; a vulgar person. [Obs.]
      [1913 Webster]

            These vile vulgars are extremely proud. --Chapman.
      [1913 Webster]

   2. The vernacular, or common language. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

vulgar
    adj 1: lacking refinement or cultivation or taste; "he had
           coarse manners but a first-rate mind"; "behavior that
           branded him as common"; "an untutored and uncouth human
           being"; "an uncouth soldier--a real tough guy";
           "appealing to the vulgar taste for violence"; "the vulgar
           display of the newly rich" [syn: coarse, common,
           rough-cut, uncouth, vulgar]
    2: of or associated with the great masses of people; "the common
       people in those days suffered greatly"; "behavior that
       branded him as common"; "his square plebeian nose"; "a vulgar
       and objectionable person"; "the unwashed masses" [syn:
       common, plebeian, vulgar, unwashed]
    3: being or characteristic of or appropriate to everyday
       language; "common parlance"; "a vernacular term"; "vernacular
       speakers"; "the vulgar tongue of the masses"; "the technical
       and vulgar names for an animal species" [syn: common,
       vernacular, vulgar]
    4: conspicuously and tastelessly indecent; "coarse language"; "a
       crude joke"; "crude behavior"; "an earthy sense of humor"; "a
       revoltingly gross expletive"; "a vulgar gesture"; "full of
       language so vulgar it should have been edited" [syn: crude,
       earthy, gross, vulgar]

Moby Thesaurus II by Grady Ward, 1.0:

173 Moby Thesaurus words for "vulgar":
   Doric, average, barbarian, barbaric, barbarous, barnyard, base,
   baseborn, below the salt, blatant, blue, boorish, brazen,
   brazenfaced, broad, cacophonous, caddish, chintzy, clumsy, coarse,
   cockney, colloquial, colorful, common, commonplace, conversational,
   crass, crude, demeaning, dirty, disadvantaged, doggerel,
   dysphemistic, earthy, everyday, extravagant, filthy, flagrant,
   flaring, flash, flaunting, frank, garish, gauche, gaudy, general,
   glaring, gorgeous, graceless, gross, gutter, harsh, homely,
   homespun, household, humble, idiomatic, ignoble, ill-bred,
   improper, impure, in bad taste, in the shade, inappropriate,
   inconcinnate, inconcinnous, inconsiderate, incorrect, indecent,
   indecorous, indelicate, inelegant, infelicitous, inferior,
   infra dig, insensitive, junior, lascivious, less, lesser, lewd,
   licentious, loathsome, loud, loutish, louty, low, low-class,
   lowborn, lowbred, lower, lowly, lurid, lustful, mean, meretricious,
   minor, modest, nasty, naughty, nonclerical, obscene, obtrusive,
   off color, offensive, ordinary, ostentatious, outlandish, plain,
   plebeian, popular, pornographic, profane, rank, raunchy, raw,
   repulsive, revolting, ribald, risque, rough, rude, salacious,
   scatological, screaming, second rank, second string, secondary,
   sensational, servile, shabby-genteel, shameless, smutty,
   spectacular, spoken, sub, subaltern, subject, subordinate,
   subservient, tactless, tasteless, tawdry, third rank, third string,
   third-estate, unbecoming, unbeseeming, uncourtly, uncouth,
   uncultivated, uncultured, underprivileged, undignified,
   uneuphonious, unfelicitous, unfeminine, unfitting, ungenteel,
   ungentle, ungentlemanly, ungraceful, unladylike, unpolished,
   unrefined, unseemly, unsolicitous, unsuitable, untasteful,
   vernacular, vile, vulgate, wild