Hit the accelerator is a phrase that is used to describe the action of increasing speed. The crossword solutions for this phrase are REV (3 letters), GUNIT (5 letters), and SPEDUP (6 letters). REV stands for revolution, which is a measure of rotational speed. GUNIT is an acronym for 'get up and go it, ' which is a phrase used to encourage someone to take action. SPEDUP is a verb meaning to move faster.