Definitions of immature:

  • adjective:   not yet mature
  • adjective:   characteristic of a lack of maturity
    Example: "Immature behavior"
  • adjective:   lacking in development
    Example: "Immature plans"
  • adjective:   (used of living things especially persons) in an early period of life or development or growth
  • adjective:   (of birds) not yet having developed feathers
  • adjective:   not fully developed or mature; not ripe