1880 (the noun, ephebe, is attested from 1690s), from Greek ephebos "of age 18-20," from epi "upon" (see epi-) + hebe "early manhood," from PIE *yegw-a- "power, youth, strength." In classical Athens, a youth of 18 underwent his dokimasia, had his hair cut off, and was enrolled as a citizen. His chief occupation for the next two years was garrison duty.
ephebic e·phe·bic (ĭ-fē'bĭk)
Of or relating to the period of puberty or adolescence.