Rubato, from the Italian rubare, “to rob”, describes expressive freedom of tempo: a performer lingers on some notes or phrases and hurries others, “stealing” time and giving it back. It is rarely written in the score and is left to the player’s judgement. In some styles only the melody moves freely while the accompaniment keeps strict time, which is typical of jazz singers and soloists phrasing across a steady band; in others the whole ensemble breathes together.
Jazz ballads often open with a rubato introduction, a pianist or guitarist playing out of tempo before the band sets the beat. Since most lo-fi is built on a looping grid, true rubato is rare there, but some jazz lo-fi tracks begin or end with a free-time piano or guitar passage, which creates a pleasant contrast when the beat finally arrives.