accelerative

adj. tending to increase speed

In physics, acceleration is defined as the rate of change of velocity, or, equivalently, as the second derivative of position. It is thus a vector quantity with dimension length/time². In SI units, acceleration is measured in metres/second² (m·s-²). The term "acceleration" generally refers to the change in instantaneous velocity.
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Adjective
1. tending to increase velocity
(synonym) acceleratory
(similar) increasing

adj. accelerative, tending to increase speed

(a.)
Relating to acceleration; adding to velocity; quickening.