1. Thick, yellowish-brown fogs that occurred in London and other industrial cities, caused by air pollution and moisture.
Usage: British; historical; informal; plural form; singular is peasouper
2. A person of Irish descent, especially an Irish immigrant.
Usage: British; informal; offensive; slang; dated

Examples

• The peasoupers of Victorian London made it difficult for people to see more than a few feet ahead.
• During the Great Smog of 1952, peasoupers blanketed the city for days.
• The industrial revolution created the notorious peasoupers that plagued London's streets.
• Visibility was reduced to almost nothing during the worst peasoupers.
• Modern air quality regulations have eliminated the thick peasoupers that once choked industrial cities.