adolescent vs immature

adolescent is a noun but immature is not a noun.

Word	Noun	Adjective	Verb	Adverb
adolescent	Yes	Yes	No	No
immature	No	Yes	No	No

adolescent (noun)	immature (noun)
a juvenile between the onset of puberty and maturity

adolescent (adjective)	immature (adjective)
relating to or peculiar to or suggestive of an adolescent	not yet mature
in the state of development between puberty and maturity	characteristic of a lack of maturity
displaying or suggesting a lack of maturity	(used of living things especially persons) in an early period of life or development or growth
being of the age 13 through 19	(of birds) not yet having developed feathers
	not fully developed or mature; not ripe