is a specific kind of: individual, mortal, person, somebody, someone, soul.

is a broader term that covers: preteen, preteenager | adolescent, stripling, teen, teenager | child, fry, kid, minor, nestling, nipper, shaver, small fry, tiddler, tike, tyke, youngster | ingenue | spring chicken, young person, younker, youth.

has as a part: juvenile body.

is the opposite of: adult, grownup.

derivation: juvenile.