whatever (pron.)youdaoicibaDictYouDict[whatever 词源字典]
mid-14c., "what in the world," emphatic of what, with ever. From late 14c. as "anything at all; all of; no matter what or who." From late 14c. as an adjective, "any sort of, any, every; no matter what, regardless of what." From 1870 as "whatever may be the cause, at any event," which could be the source of the modern teen slang dismissive use.[whatever etymology, whatever origin, 英语词源]