Source : Webster's Revised Unabridged Dictionary (1913)

Coarse \Coarse\, a. [Compar. {Coarser}; superl. {Coarsest}.] [As
   this word was anciently written course, or cours, it may be
   an abbreviation of of course, in the common manner of
   proceeding, common, and hence, homely, made for common
   domestic use, plain, rude, rough, gross, e. g., ``Though the
   threads be course.'' --Gascoigne. See {Course}.]
   1. Large in bulk, or composed of large parts or particles; of
      inferior quality or appearance; not fine in material or
      close in texture; gross; thick; rough; -- opposed to
      {fine}; as, coarse sand; coarse thread; coarse cloth;
      coarse bread.

   2. Not refined; rough; rude; unpolished; gross; indelicate;
      as, coarse manners; coarse language.

            I feel Of what coarse metal ye are molded. --Shak.

            To copy, in my coarse English, his beautiful
            expressions.                          --Dryden.

   Syn: Large; thick; rough; gross; blunt; uncouth; unpolished;
        inelegant; indelicate; vulgar.

Source : WordNet®

coarse
     adj 1: of texture; large-grained or rough to the touch; "coarse
            meal"; "coarse sand"; "a coarse weave" [ant: {fine}]
     2: 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: {common}, {rough-cut}, {uncouth}, {vulgar}]
     3: of low or inferior quality or value; "of what coarse metal
        ye are molded"- Shakespeare; "produced...the common cloths
        used by the poorer population" [syn: {common}]
     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}]