source: The Ultimate Guide To Coarse Ground Coffee

1. rough or loose in texture or grain:

〈表面･生地･肌などが〉きめの粗い, ざらざらした

e.g. a coarse woolen cloth.

made of large grains or particles:

〈粉などが〉粒の大きい; 〈髪の毛などが〉硬い

e.g. dry, coarse sand.

(of grains or particles) large.

(of a person's features) not elegantly formed or proportioned.

(of food or drink) of inferior quality.

〈品質･食物などが〉粗悪な, 粗末な

2. (of a person or their speech) rude, crude, or vulgar.

〈言葉･ふるまいなどが〉粗野な, 下品な, 卑猥（ひわい）な

coarsish adjective

late Middle English (in the sense ‘ordinary or inferior’): origin uncertain; until the 17th century identical in spelling with course, and possibly derived from the latter in the sense ‘ordinary manner’.