Lewis & Short

gymnas, ădis, f., = γυμνάς, wrestling, the exercise of wrestling (in post-Aug. poetry): Herculeā turpatus gymnade, Stat. Th. 4, 106; id. S. 4, 2, 47; Prud. Cont. Sym. 2, 517.
Plur.: exercere protervas Gymnadas, Stat. Ach. 1, 358.