What do rappers mean by “Spit” or “Spitting”?
The slang terms “Spit” and “Spitting” (also spelled “Spittin'”) are verbs which is used in rap/hip-hop music to represent the action of rapping.
Spit means to rap; rhyme and flow.
Spitting means to be rapping.
Read: What does “Remix” mean?