Webster's Revised Unabridged Dictionary · 1913

Rapper

Rapper (rap"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
3.
A musician specializing in rap music.