1. (of birds) not yet having developed feathers

    Synonyms : unfledged
  2. (used of living things especially persons) in an early period of life or development or growth

    Synonyms : young
  3. not fully developed or mature; not ripe

    Synonyms : green, unripe, unripened
  4. characteristic of a lack of maturity

    Antonyms : mature
    Examples :
    • immature behavior
  5. not yet mature

    Antonyms : mature