Where does “smog” come from?

smog (Serbo-Croatian) comes from English smog, from English smoke, from Middle English smoke, from Old English smoca, from Proto-Germanic smukô, from Danish smug- — secretly.

smog (Serbo-Croatian): smog

Definitions

smog

Ancestry of “smog”, step by step

Step	Language	Word	Meaning
1	English	smog	A noxious mixture of particulates and gases that...
2	English	smoke	The visible vapor/vapour, gases, and fine...
3	Middle English	smoke	smoke
4	Old English	smoca	smoke
5	Proto-Germanic	smukô	smoke, nebulous air
6	Danish	smug-	secretly

Every word from Danish smug- →Every word from Proto-Germanic smukô →Every word from Old English smoca →