Definition of Vulgar, Vulgarity and Vulgarism:

Vulgar
Definition :
1. Crudely indecent.
2.
   a. Deficient in taste, delicacy, or refinement.
   b. Marked by a lack of good breeding; boorish.
   c. Offensively excessive in self-display or expenditure;
3. Spoken by or expressed in language spoken by the common people;
4. Of or associated with the great masses of people; common.

Synonyms :
ordinary, familiar, public, impolite, popular, indecent, improper, dirty.

Antonyms :
decent, inoffensive, nice, polite, refined, artistic, fashionable.
Vulgarity
Definition :
1. The quality or condition of being vulgar.
2. Something, such as an act or expression, that offends good taste or propriety.

Synonyms :
porn, pornography, indecency, obscenity, profanity, rudeness.

Antonyms :
cleanness, decency, innocence, morality, decorum, restraint, tastefulness.
Vulgarism
Definition :
1. Vulgarity.
2.
   a. A crudely indecent word or phrase; an obscenity.
   b. A word, phrase, or manner of expression used chiefly by uneducated people.

Synonyms :
barbarism, decay, distortion, foulness, infection, putrefaction, rottenness, impropriety, inhumanity.

Antonyms :
kindness, praise, correctness, propriety, suitability, tastefulness.