- rap (n.)
- early 14c., "a quick, light blow, stroke," also "a fart" (late 15c.), native or borrowed from a Scandinavian source (cf. Danish rap, Swedish rapp "light blow"); either way probably of imitative origin (cf. slap, clap). Slang meaning "rebuke, blame, responsibility" is from 1777; specific meaning "criminal indictment" (cf. rap sheet, 1960) is from 1903. Meaning "music with improvised words" first in New York City slang, 1979.
- rap (v.)
- mid-14c., "strike, smite, knock," from rap (n.). Meaning "talk informally" is first recorded 1929, popularized c.1965 in Black English, possibly first in Caribbean English, from British slang meaning "say, utter" (1879), originally "to utter a sudden oath" (1540s), ultimately from rap (n.). Meaning "to perform rap music" is recorded by 1979. Related: Rapped; rapping. To rap (someone's) knuckles "give light punishment" is from 1749.