vague (adj.)youdaoicibaDictYouDict[vague 词源字典]
"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.[vague etymology, vague origin, 英语词源]