immature

As an adjective immature

is not fully formed or developed, unripe, not mature.

As a noun dependent is

.

Uninitiated is a related term of immature.

As adjectives the difference between uninitiated and immature

is that uninitiated is not having been initiated while immature is not fully formed or developed, unripe, not mature.

As adjectives the difference between immature and simple

is that immature is not fully formed or developed, unripe, not mature while simple is uncomplicated; taken by itself, with nothing added.

As a noun simple is

a preparation made from one plant, as opposed to something made from more than one plant.

As a verb simple is

to gather simples, ie, medicinal herbs.

As adjectives the difference between immature and puerile

is that immature is not fully formed or developed, unripe, not mature while puerile is characteristic of, or pertaining to, a boy or boys; confer: puellile.

Immature is a related term of girlish.

As adjectives the difference between immature and girlish

is that immature is not fully formed or developed, unripe, not mature while girlish is like a girl; feminine.

Immature is a related term of harebrained.

As adjectives the difference between immature and harebrained

is that immature is not fully formed or developed, unripe, not mature while harebrained is (of an idea or plan etc) absurd, foolish or stupid.

Unpractised is a related term of immature.

As adjectives the difference between unpractised and immature

is that unpractised is while immature is not fully formed or developed, unripe, not mature.

Unfamiliar is a related term of immature.

As adjectives the difference between unfamiliar and immature

is that unfamiliar is strange, not familiar while immature is not fully formed or developed, unripe, not mature.

As a noun unfamiliar

is an unfamiliar person; a stranger.

Incipient is a related term of immature.

As adjectives the difference between incipient and immature

is that incipient is in an initial stage; beginning, starting, coming into existence while immature is not fully formed or developed, unripe, not mature.

As a noun incipient

is (countable|obsolete) beginner.

Unaccustomed is a related term of immature.

As adjectives the difference between unaccustomed and immature

is that unaccustomed is not prepared by life experience to an event or thing, not accustomed while immature is not fully formed or developed, unripe, not mature.