Freestyle rap is an improvisational form of rapping, performed with few or no previously composed lyrics, which is said to reflect a direct mapping of the mental state and performing situation of the artist. It is non-scripted, non-rehearsed, uncut, and the rawest form of hip-hop. Artists will often refer to places and objects in their immediate setting. Freestyle rapping forces an individual to think on the spot, describe their surroundings, and, to a certain degree, rap uncensored from what is inside. It is similar in this sense to improvisational music or acting and draws comparisons to improvisational jazz in particular.

Freestyles are performed a cappella, over beatboxing and over instrumental versions of recorded hip hop songs. Impromptu raps in this style are called freestyles even if they are entirely pre-written and memorized.