adj. 1. Not fully grown or developed: an immature plant. 2. Marked by or suggesting a lack of normal maturity: silly, immature behavior. See Synonyms at young. n. An immature animal; a juvenile. [Latin immātūrus : in-, not; see IN-1 + mātūrus, mature; see mā-1 in the Appendix of Indo-European roots.] im′ma·turely adv. im′ma·turi·ty, im′ma·tureness n. |
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