agent noun meaning "one who raps" in any sense (see rap, v.). Before the hip-hpo performance sense emerged c.1979, it could mean "door-knocker" (1630s), "spirit-rapper" (1755), "professional perjurer" (1840), prison slang for "prosecutor" (1904), "itinerant antiques buyer," with a tinge of shadiness (1914). Rapster is from 1772.