Added 10 October 2026 smog /smɒɡ/ noun Categories: Describing WordsRare Words noun ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about smog at Wordnik → Where our words come from → A noxious mixture of particulates and gases that is the result of urban air pollution. verb To get a smog check; to check a vehicle or have it checked for emissions. If the car is more than five years old, you'll have to have it smogged before you can register it. Origin Blend of smoke + fog. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: smogginesshazepollutionfogmistairphotochemicalsmokeaccumulatorsmoggycontributionsmaze Back to today's word