A cycling sprinter is a road bicycle racer or track racer

Track cycling

Track cycling is a bicycle racing sport usually held on specially built banked tracks or velodromes using track bicycles....

 who can finish a race very explosively by accelerating

Acceleration

In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...

 quickly to a high speed, often using the slipstream

Slipstream

A slipstream is a region behind a moving object in which a wake of fluid is moving at velocities comparable to the moving object . The term slipstream also applies to the similar region adjacent to an object with a fluid moving around it...

 of another cyclist or group of cyclists tactically to conserve energy.
Sprinters have a higher ratio of fast-twitch muscle fibers than non-sprinters. Road cycling sprinters sometimes tend to have a larger build than the average road racing cyclist, combining the strength of their legs with their upper body to produce a short burst of speed necessary in a closely contested finish.