1572 (implied in scabrously), from L.L. scabrosus "rough," from L. scaber "rough, scaly," related to scabere "to scratch, scrape" (see scabies). Sense in Eng. evolved from "harsh, unmusical," to "vulgar" (1881), "squalid" (1939) and "nasty, repulsive" (c.1951).