The difference between Immature and Mature

When used as adjectives, immature means not fully formed or developed, unripe, not mature, whereas mature means fully developed.

Immature is also noun with the meaning: an immature member of a species.

Mature is also verb with the meaning: to become mature.

check bellow for the other definitions of Immature and Mature

Immature as an adjective:

Not fully formed or developed, unripe, not mature.
Immature as an adjective:

Childish in behavior, not mature.

Examples:

"You're only young once, but you can be immature the rest of your life."

"The man was immature for throwing a tantrum."

Mature as an adjective:

Fully developed; grown up in terms of physical appearance, behaviour or thinking; ripe.

Examples:

"She is quite mature for her age."
Mature as an adjective:

Brought to a state of complete readiness.

Examples:

"a mature plan"
Mature as an adjective:

Profound; careful.

Examples:

"The headmaster decided to expel the boy after a mature consideration."
Mature as an adjective (medicine, obsolete):

Come to, or in a state of, completed suppuration.

Mature as a verb (intransitive, of food, especially fruit):

To become mature; to ripen.
Mature as a verb (intransitive):

To gain experience or wisdom with age.
Mature as a verb (transitive):

To make something mature.
Mature as a verb (intransitive, finance):

To reach the date when payment is due