red-hot (adj.)youdaoicibaDictYouDict[red-hot 词源字典]
late 14c., "heated till it glows red" (of metal, etc.); of persons, "lively, passionate," it is recorded from c. 1600. Red-hot mama is 1926, jazz slang, "earthy female singer," also "girlfriend, lover."[red-hot etymology, red-hot origin, 英语词源]