par·a·site | \ˈper-ə-ˌsīt, ˈpa-rə-\

Definition of parasite 

1 : a person who exploits the hospitality of the rich and earns welcome by flattery sought to rid the palace of the parasites of his prosperity

2 : an organism living in, with, or on another organism in parasitism an intestinal parasite of humans a parasite that causes malaria

3 : something that resembles a biological parasite in dependence on something else for existence or support without making a useful or adequate return That city has become a parasite on the country.

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Choose the Right Synonym for parasite

parasite, sycophant, toady, leech, sponge mean a usually obsequious flatterer or self-seeker. parasite applies to one who clings to a person of wealth, power, or influence or is useless to society. a jet-setter with an entourage of parasites sycophant adds to this a strong suggestion of fawning, flattery, or adulation. a powerful prince surrounded by sycophants toady emphasizes the servility and snobbery of the self-seeker. cultivated leaders of society and became their toady leech stresses persistence in clinging to or bleeding another for one's own advantage. a leech living off his family and friends sponge stresses the parasitic laziness, dependence, and opportunism of the cadger. a shiftless sponge, always looking for a handout

Examples of parasite in a Sentence

Many diseases are caused by parasites. She's a parasite who only stays with him for the money. These new companies are parasites feeding off the success of those who spent the last decade establishing the industry.
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Recent Examples on the Web

But other researchers of this disease are conflicted about the study’s method, fearing there is no way to be sure that all of the tiny parasites have been evicted from the hosts when the trial ends. Heather Murphy, New York Times, "They’re Hosting Parasitic Worms in Their Bodies to Help Treat a Neglected Disease," 1 Mar. 2018 Toxoplasmosis is a disease spread by parasites in the feces of cats. New York Times, "Orcas of the Pacific Northwest Are Starving and Disappearing," 9 July 2018 Another type of beneficial gene might kill malaria parasites in mosquitoes before they can be transmitted, a strategy known as population modification. Anthony A. James, STAT, "Gene-drive technology must be developed in a safe, ethical way," 10 July 2018 And this repulsive encounter is worse than unhygienic: those feces spread microscopic parasites that cause Chagas disease. Katherine J. Wu, Smithsonian, "How Tiny Trackers Could Help Humans Avoid Kissing Bugs’ Deadly Smooch," 9 July 2018 Most of the remaining outbreaks were caused by parasites transmitted by birds present in recreational waters, toxins and chemicals or harmful algal blooms, the report says. Jamie Ducharme, Time, "Why July Is the Most Dangerous Month To Go Swimming," 28 June 2018 Also inside are medicine to kill parasites -- doctors found worms in the stomach of a soldier who darted across the DMZ last year to defect -- and a USB stick full of videos with information from the outside world. Ivan Watson, Jungeun Kim, Stella Ko And Jo Shelley, CNN, "Messages in bottles sent across the sea to North Korea," 17 May 2018 Molting provides new sensory and protective hairs, and helps shed external parasites. Amy Rankin, National Geographic, "A Tarantula Sheds Its Skin in New Time-Lapse Video," 16 May 2018 Tick season is upon us, which means that more and more people are going to start becoming infected with illnesses caused by the parasites. Elana Glowatz, Newsweek, "Tick Season Facts: How to Prevent Parasite-Borne Diseases," 13 Mar. 2018

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

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First Known Use of parasite

1539, in the meaning defined at sense 1

History and Etymology for parasite

Middle French, from Latin parasitus, from Greek parasitos, from para- + sitos grain, food

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Statistics for parasite

Last Updated

17 Oct 2018

Look-up Popularity

Time Traveler for parasite

The first known use of parasite was in 1539

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More Definitions for parasite



English Language Learners Definition of parasite

: an animal or plant that lives in or on another animal or plant and gets food or protection from it

: a person or thing that takes something from someone or something else and does not do anything to earn it or deserve it


par·a·site | \ˈper-ə-ˌsīt \

Kids Definition of parasite

1 : a living thing (as a flea, worm, or fungus) that lives in or on another living thing and gets food and sometimes shelter from it and usually causes harm to it

2 : a person who lives at the expense of another


par·a·site | \ˈpar-ə-ˌsīt \

Medical Definition of parasite 

: an organism living in, with, or on another organism in parasitism

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Comments on parasite

What made you want to look up parasite? Please tell us where you read or heard it (including the quote, if possible).


to reject or criticize sharply

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