juvenile

nouns

a young person, not fully developed

antonym

of or relating to or characteristic of or appropriate for children or young people

"juvenile diabetes"; "juvenile fashions"

juvenile

is derived from

pertains to

displaying or suggesting a lack of maturity

"adolescent insecurity"; "jejune responses to our problems"; "their behavior was juvenile"; "puerile jokes"

adolescent, jejune, juvenile, puerile

is derived from