• (a.) Not having arrived at puberty; immature.
Im·pu'ber·al (ĭm*pū'bẽr* a l) adjective Not having arrived at puberty; immature. « In impuberal animals the cerebellum is, in proportion to the brain proper, greatly less than in adults.» Sir W. Hamilton. 
impuberal Not having arrived at puberty; immature.