a form of air pollution that is or looks like a mixture of smoke and fog, especially in cities attempts to reduce smog caused by traffic fumes More Like ThisBlended or portmanteau wordsalcopop, breathalyser, bromance, brunch, chillax, chugger, docusoap, edutainment, greenwash, guesstimate, infomercial, mechatronics, metrosexual, mockney, motel, multiplex, pleather, podcast, robocall, simulcast, sitcom, smog, staycation, telethon, televangelist, workaholic See worksheet. See related entries: Waste and pollution Word Origin early 20th cent.: blend of smoke and fog.Extra examples Smog levels are high today. a layer of smog over the city measures to reduce smog Nowadays, smogs are very common in major cities. The city has had only limited success in reducing smog levels. The streets are clean, there’s no traffic, and there’s no smog to block out the sunshine.