Definitions of rap:

• noun:   genre of African-American music of the 1980s and 1990s in which rhyming lyrics are chanted to a musical accompaniment; several forms of rap have emerged
• noun:   voluble conversation
• noun:   a gentle blow
• noun:   a reproach for some lapse or misdeed

  Example: "It was a bum rap"

• noun:   the sound made by a gentle blow
• noun:   the act of hitting vigorously
• verb:   talk volubly
• verb:   strike sharply

  Example: "Rap him on the knuckles"

• verb:   perform rap music
• verb:   make light, repeated taps on a surface