of clothing or garments, "rough, shaggy," c. 1300 (late 12c. in surnames), past-participle adjective as though from a verb form of rag (n.1). Compare Latin pannosus "ragged, wrinkly," from pannus "piece of cloth." But ragged might reflect a broader, older meaning of the noun rag (n.1), perhaps from or reinforced by Old Norse raggaðr "shaggy," via Old English raggig "shaggy, bristly, rough" (which, Barnhart writes, "was almost surely developed from Scandinavian").
Of persons, "wearing tattered clothes," late 14c. From late 14c. of plants or leaves, "serrated." To run (someone) ragged is from 1915. Related: Raggedly; raggedness.