WordNet sense 1 (distance travelled per unit time):

velocity

WordNet sense 2 (the ratio of the focal length to the diameter of a (camera) lens system):

focal ratio, f number, stop number

WordNet sense 3 (a rate (usually rapid) at which something happens):

fastness, swiftness

WordNet sense 4 (a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression):

amphetamine, upper, pep pill

WordNet sense 5 (step on it):

hasten, hie, hotfoot, race, rush, belt along, bucket along, cannonball along, pelt along, rush along

WordNet sense 6 (move very fast):

hurry, zip, travel rapidly

WordNet sense 7 (cause to move faster):

accelerate

WordNet sense 8 (move faster):

quicken

WordNet sense 9 (changing location rapidly):

speeding, hurrying