pest

play

noun \ˈpest\

Definition of pest

1 : an epidemic disease associated with high mortality; specifically : plague
2 : something resembling a pest in destructiveness; especially : a plant or animal detrimental to humans or human concerns (such as agriculture or livestock production)
3 : one that pesters or annoys : nuisance

pesty

play \ˈpe-stē\ adjective

See pest defined for English-language learners

See pest defined for kids

Examples of pest in a Sentence

These insects are pests for farmers.
mice and other household pests
You're being a real pest. Would you leave us alone, please?

Recent Examples of pest from the Web

Researchers realised, soon after the discovery of gene drives half a century ago, that they might be forged into tools for eradicating diseases and pests.

— The Economist, "Gene drivesA promising means of pest control meets some evolutionary truths," 22 July 2017
The Kansas City Health Department cited d’Bronx Authentic Deli and Pizzeria, 3904 Bell St., for not having effective pest control measures in place.

— joyce smith, kansascity.com, "Olathe McDonald’s and d’Bronx on 39th are cited for roach infestations," 5 July 2017
Keeping the grill grates clean prevents the buildup of bacteria, discourages bugs and pests from trying to check out your grill, and prevents carbon buildup which can eventually alter the performance of your grill.

— timothy dahl, Popular Mechanics, "The Beginner's Guide to Grilling Any Type of Food," 1 July 2017
Around the same time the baby pumpkins are appearing on the vine, the pests show up.

— arricca sansone, Country Living, "Everything You Need to Know About Planting Pumpkin Seeds," 29 June 2017
The EPA approved a new Monsanto biotechnology last week: Corn seeds will be genetically modified to produce an insecticide that in turn kills pests (in this case, western corn rootworms) by disrupting their RNA.

— rosa inocencio smith, The Atlantic, "The Atlantic Daily: Presidential Legitimacy and Preexisting Conditions," 23 June 2017
So, yeah, paying attention and [being] interested to see what happens but also trying to leave them alone to do their jobs and not be a pest.

— joanna robinson, The Hive, "The Sci-Fi Guru Who Predicted Google Earth Explains Silicon Valley’s Latest Obsession," 23 June 2017
Its pest control company arrived during the inspection.

— joyce smith, kansascity.com, "Nine Kansas, Kansas City food operations cited for roach infestations," 22 June 2017
While other bacteria, such as delftia, tend to keep the pests away.

— john pacenti, ajc, "Why do mosquitoes bite you, but not your friend?," 21 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pest.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of pest

Middle French peste, from Latin pestis

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First Known Use: 15th century

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PEST Defined for English Language Learners

pest

play

noun

Definition of pest for English Language Learners

: an animal or insect that causes problems for people especially by damaging crops
: a person who bothers or annoys other people

PEST Defined for Kids

pest

play

noun \ˈpest\

Definition of pest for Students

1 : nuisance … Kirsti was such a pest, always butting in. — Lois Lowry, Number the Stars
2 : a plant or animal that is harmful to humans or property
3 : pestilence

Medical Dictionary

pest

play

noun \ˈpest\

Medical Definition of pest

1: an epidemic disease associated with high mortality; specifically : plague 2
2: something resembling a pest in destructiveness; especially : a plant or animal detrimental to humans or human concerns