Words related to rap
c. 1300, "to strike with a quick, sharp motion, to slap," from Old English clæppan "to throb, beat," or from or influenced by its Old Norse cognate, klappa, a common Germanic echoic verb (compare Old Frisian klapa "to beat," Old High German klaphon, German klappen, Old Saxon klapunga).
Meaning "to make a sharp noise" is late 14c. Of hands, "to beat together to get attention or express joy," from late 14c. Without specific mention of hands, "to applaud, to manifest approbation by striking the hands together," 1610s. To clap (someone) on the back is from 1520s and retains the older sense. Related: Clapped; clapping.
"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.