rapper (n.)

"one who or that which raps" in any sense, 1610s; see rap (v.)). It could mean "door-knocker" (1630s), "spirit-rapper" (1755), "professional perjurer" (1840), prison slang for "prosecutor" in prison slang (1904), "itinerant antiques buyer," with a tinge of shadiness (1914). The hip-hop performance sense emerged c. 1979. Rapster is from 1772.