late 15c., obscurite, "absence of light, lack of brightness or luster;" 1610s with the meaning "condition of being unknown or inconspicuous;" from obscure (adj.) + -ity; or else from Old French obscurete, a variant of oscureté "darkness, gloom; vagueness, confusion; insignificance" (14c.) and directly from Latin obscuritatem (nominative obscuritas) "darkness, indistinctness, uncertainty," from obscurus. Meaning "quality or condition of not being clearly comprehended" is from late 15c. (Caxton).
When I was asked to talk about the Obscurity of the Modern Poet I was delighted, for I have suffered from this obscurity all my life. But then I realized that I was being asked to talk not about the fact that people don't read poetry, but about the fact that most of them wouldn't understand it if they did .... [Randall Jarrell, "The Obscurity of Poetry," 1953]