Immature/ˌɪməˈtʃʊr,ˌɪməˈtʊr/ Definition 1 of 5Pro Tip 1/2Physical Growth Refers to organisms or objects not reaching their full size or potential. The immature sapling swayed in the gentle breeze. Pro Tip 2/2Premature Judgment Avoid judging something as 'immature' before it has time to develop. It's too early to eat these berries; they're immature.