A gymnast is a person who trains in and practices the sport of gymnastics. If you become a gymnast, you'll learn to walk and jump and even do cartwheels on a balance beam.
Athletes who participate in gymnastics are gymnasts. During competitions, gymnasts perform routines on uneven and parallel bars; vault over a special "horse" or table; and demonstrate a series of floor moves including back flips, handstands, and leaps. Gymnast comes from gymnastics, which is based on the Greek gynmastikos, "skilled in bodily exercise," from the root gymnazein, "to exercise."