'Impuberal' definitions:

Definition of 'Impuberal'

From: GCIDE

Impuberal \Im*pu"ber*al\ ([i^]m*p[=u]"b[~e]r*al), a. Not having arrived at puberty; immature. [1913 Webster]
In impuberal animals the cerebellum is, in proportion to the brain proper, greatly less than in adults. --Sir W. Hamilton. [1913 Webster]