Immature
Origin
From Middle French immature
Full definition of immature
Adjective
immature
- Not fully formed or developed, unripe.
- Silly or childish in behavior.You're only young once, but you can be immature the rest of your life.
- - As quoted in The Catcher in the Rye (1951) by .The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one.