a person or thing that annoys, esp by imposing itself when it is not wanted; nuisance
any organism that damages crops, injures or irritates livestock or man, or reduces the fertility of land
( as modifier )
pest control
rare an epidemic disease or pestilence
First recorded in 1545–55, pest is from the Latin word pestis plague
A pest is something or someone that bugs you. That annoying mosquito that keeps you up at night is a pest, and so is that younger brother who wants to control the TV remote. An unwanted, bothersome person is a pest — and so is an unwanted, bothersome bug. In fact, the "destructive or harmful insect" definition came before "annoying person," following the "plague or pestilence" meaning of pest. The Latin root is pestis, "deadly contagious disease." During the Late Middle Ages, when the bubonic plague killed a third of all humans, it was commonly known as "the pest."
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
They also provide natural pest control, preying on insects such as caterpillars and aphids that can damage trees, helping to regulate insect populations and support the long-term health of the woodland.
From BBC • Jun. 28, 2026
On his cow-calf operation in the state’s southeastern plains, Diebel is already limiting opportunities for the pest to infest his herd.
From The Wall Street Journal • Jun. 12, 2026
Still, the re-emergence of the pest in Texas near the southern U.S. border wasn’t surprising, given that it has been known to be present among cattle in Mexico.
From MarketWatch • Jun. 10, 2026
The outbreak has triggered a race to keep the pest from spreading.
From Barron's • Jun. 6, 2026
“Unless you count Old-Green-Grasshopper over there. But he is long past it now. He is too old to be a pest any more.”
From "James and the Giant Peach" by Roald Dahl
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
