downright (adv.)

c. 1200, "straight down, right down, perpendicularly," from down (adv.) + right (adj.1). Meaning "thoroughly, completely, utterly," often merely emphatic, is attested from c. 1300. As an adjective, "complete, absolute," from 1560s. Old English had dunrihte "downwards." The inverted form right-down is attested 17c.