Immature (adjective)

1. Not fully developed or grown; immature.
2. Not having reached a desired or final stage of development.
3. Lacking the maturity, judgment, or responsibility expected of an adult.

Origin:

From latin immaturus, from in- + maturus, ripe.

Examples:

1. The fruit was picked before it was mature and was not yet ripe.
2. He was criticized for his immature behavior at the party.
3. The young athlete's game was still immature and needed more work.
4. The student's writing was immature and needed more development.
5. The company's management team was criticized for its immature handling of the crisis.