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late 15c., "absence of light;" 1610s with meaning "condition of being unknown;" from obscure (adj.) + -ity; or else from Middle French obscurité, variant of Old French oscureté "darkness, gloom; vagueness, confusion; insignificance" (14c.), from Latin obscuritatem (nominative obscuritas) "darkness, indistinctness, uncertainty," from obscurus.