Coarse, a. [Compar. Coarser; superl. Coarsest.]
Etymology: [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.
Shades of meaning
Fernald has no entry of its own for coarse; he lists it under bluff, brutish, large, rustic.
He lists it without comment; the entries above explain its neighbors.