Synonyms for Formative (same or very similar meaning)
WordNet sense 1 ((used of living things especially persons) in an early period of life or development or growth):
immature, young
WordNet sense 2 (forming or capable of forming or molding or fashioning):
plastic, shaping
WordNet sense 3 (constructing or tending to construct or improve or promote development):
constructive
From the ODE community, based on WordNet
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