Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† gymnastĭcus, a, um, adj., = γυμναστικός, of or belonging to bodily exercise, gymnastic (Plautinian, for which Cic. uses gymnicus): pro exercitu gymnastico et palaestrico hoc habemus, Plaut. Rud. 2, 1, 7: arte gymnastica, disco, hasta, pila, id. Most. 1, 2, 72 (a spurious line).