Juvenile

As an adjective juvenile

is youthful; young.

As a noun teenagehood is

the state of being in one's teenage years.

As a noun childhood

is (uncountable) the state of being a child.

As an adjective juvenile is

youthful; young.

As adjectives the difference between pretentious and juvenile

is that pretentious is marked by an unwarranted claim to importance or distinction while juvenile is youthful; young.

As adjectives the difference between juvenile and sophomoric

is that juvenile is youthful; young while sophomoric is of, relating to, or characteristic of a sophomore.

As adjectives the difference between juvenile and undefined

is that juvenile is youthful; young while undefined is lacking a definition or value.

As adjectives the difference between juvenile and jovial

is that juvenile is youthful; young while jovial is (obsolete) pertaining to jove or zeus; jovian.

As an adjective juvenile

is youthful; young.

As a noun kid is

a young goat or kid can be a fagot; a bundle of heath and furze.

As a verb kid is

(colloquial) to make a fool of (someone).

As adjectives the difference between vigorous and juvenile

is that vigorous is physically strong and active while juvenile is youthful; young.

As adjectives the difference between juvenile and senseless

is that juvenile is young; not fully developed while senseless is bereft of feeling or consciousness; deprived of sensation; unconscious; insensible.

As a noun juvenile

is a prepubescent child.