Immature, inexperienced, and lacking the knowledge or judgment that comes with maturity; youthful and innocent in a naive way.
From Old English 'calu' (bald) related to Latin 'calvus.' Originally referred to birds without feathers; evolved to mean young/immature, then developed the sense of naively inexperienced.
The word originally meant 'bald' because young birds without their adult feathers looked naked and unfinished—over time, the literal image transformed into a metaphor for anyone unfinished or incomplete in judgment.
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