muggy (adj.)youdaoicibaDictYouDict[muggy 词源字典]
1731, from mugen "to drizzle" (late 14c.), from a Scandinavian source such as Old Norse mugga "drizzling mist," possibly from PIE *meug- "slimy, slippery" (see mucus).[muggy etymology, muggy origin, 英语词源]