haze (n.)youdaoicibaDictYouDict[haze 词源字典]
"opaqueness of the atmosphere," 1706, probably a back-formation of hazy (q.v.). Sense of "confusion, vagueness" is 1797. The differentiation of haze, mist, fog (and other dialectal words) is unmatched in other tongues, where the same word generally covers all three and often "cloud" as well; this may be an effect of the English climate on the English language.[haze etymology, haze origin, 英语词源]
obscurity (n.)youdaoicibaDictYouDict
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.
vague (adj.)youdaoicibaDictYouDict
"uncertain as to specifics," 1540s, from Middle French vague "empty, vacant; wild, uncultivated; wandering" (13c.), from Latin vagus "strolling, wandering, rambling," figuratively "vacillating, uncertain," of unknown origin. Related: Vagueness.