pre·ma·ture / ˌprēməˈchoŏr; -ˈt(y)oŏr/ • adj. occurring or done before the usual or proper time; too early: the sun can cause premature aging| it would be premature to do so at this stage. ∎ (of a baby) born before the end of the full term of gestation, esp. three or more weeks before.DERIVATIVES: pre·ma·ture·ly adv. prematurely gray hair.pre·ma·tu·ri·ty / -ˈchoŏritē; -ˈt(y)oŏr-/ n.