

from Childish Gambino – Bonfire Lyrics on Genius


He’s claiming the beat is so good it’s “retarded.” “Slow” is a euphemism for retarded; therefore, the song is a “slow jam,” also another term for an down-tempo R&B ballad. (Interesting side note: in Italian, music played slowly is called ritardando.)

It can also be a reference to slowing the beat down from the standard tempo and matching your rapping/vocals accordingly, which is called retarding the music.
