1) Critic 2) Doorknocker 3) Spirit 1) LL Cool J for one 2) Bow Wow 3) Coolio 4) Door knocker 5) Drake or Future 6) Fast-talking performer 7) Freestyle performer 8) Ghostface Killah 9) Grammy nominee since 1996 10) Hammer is one 11) Hammer or Candyman 12) Hammer, once 13) Heavy D 14) Hip-hop figure 15) Hip-hop singer 16) Ice-T or Hammer 
[electrostatic precipitation] Rappers are used to transmit strong shearing forces to collecting plates in order to release deposited dust particles. Rapping is the process by which electrodes and particles are broken apart by vibrations from the rappers. Often used in electrostatic precipitators, rappers relapse the caked on dust layer whic...
• (n.) One who, or that which, raps or knocks; specifically, the knocker of a door. • (n.) A forcible oath or lie.
Rap'per (răp'pẽr) noun [ From Rap .] 1. One who, or that which, raps or knocks; specifically, the knocker of a door. Sterne. 2. A forcible oath or lie. [ Slang] Bp. Parker. 
Rapper is slang for someone who raps.
noun someone who performs rap music
an artist who performs raps over a hip hop beat - My daughter wants to be a rapper when she grows up.