Bare or naked.
[Greek gumnos, naked.]
In classical Greece, a gumnasion was a place where young men exercised naked, from which English has derived gymnasium and its relatives gymnast, gymnastic, and gymnastics. The gymnosophists (literally, naked wise men, from Greek sophistēs, a teacher of philosophy) were members of an ancient Hindu sect, known for ascetic behaviour that included wearing few clothes. The prefix appears in a number of biological and botanical terms, including gymnosperm for a class of plants—including conifers, cycads, and the ginkgo—whose seeds are not protected by an ovary or fruit.