ditzy (adj.)youdaoicibaDictYouDict[ditzy 词源字典]
also ditsy, "stupid, scatterbrained" (especially of women), by 1973, U.S. slang, of unknown origin; one guess is that it is related to earlier U.S. black slang dicty (1926) "conceited, snobbish," also of unknown origin, but the sense is very difficult. The noun ditz (1982) appears to be a back-formation.[ditzy etymology, ditzy origin, 英语词源]