par·​a·​sit·​ic | \ ˌper-ə-ˈsi-tik How to pronounce parasitic (audio) , ˌpa-rə- \
variants: or less commonly parasitical \ ˌper-​ə-​ˈsi-​ti-​kəl How to pronounce parasitic (audio) , ˌpa-​rə-​ \

Definition of parasitic

1 : of, relating to, or being a parasite: such as
a(1) : living on another organism in parasitism Some caterpillars even sport white spots that resemble the eggs of the parasitic wasps that prey upon caterpillars …— Mary Parker Sonis a parasitic yeast/plant Filariasis, caused by parasitic worms in the human lymphatic system and carried in mosquitoes, infects some eighty million people in tropical and subtropical regions of the world.— Wayne Biddle
(2) : caused by or resulting from the effects of parasites a parasitic disease/infection
(3) of a bird : laying eggs in the nest of another bird The cowbird and the cuckoo are parasitic birds.
b : exploiting the hospitality of others : depending on another or others for existence or support without making a useful or adequate return … manipulated and glorified by self-serving, parasitic northern bureaucrats.— Edward Friedman
2 phonetics : of, relating to, or constituting a speech sound that is interposed between two other sounds usually as a by-product of transition from one place of articulation to another The \ə\ in \ˈeləm\ for elm or in \ˈathəˌlēt\ for athlete, the \t\ in \fents\ for fence, and the \b\ and b in \ˈnimbəl\ nimble from Middle English nimel are parasitic.

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Other Words from parasitic

parasitically \ ˌper-​ə-​ˈsi-​ti-​kəl How to pronounce parasitic (audio) , ˌpa-​rə-​ \ adverb
During sexually quiescent phase, lampreys live simply, communally or parasitically upon other fish. — Earl W. Count … those who live parasitically on the political system … — John Derbyshire

Examples of parasitic in a Sentence

Recent Examples on the Web That can only be done by creating something other than a rent-seeking, parasitic model. Jacob Silverman, The New Republic, "Instacart Is a Parasite and a Sham," 30 Dec. 2020 Both Senkler and Petersen pointed out that a parasitic lifestyle and slow growth could enable mistletoes to subsist on low amounts of ATP. Quanta Magazine, "The Mystery of Mistletoe’s Missing Genes," 21 Dec. 2020 One reason for this prevalence may be exposure to infectious diseases endemic to the continent like tuberculosis, malaria, respiratory infections and even parasitic worms. Miriam Fauzia, USA TODAY, "Fact check: Coronavirus deaths across continent of Africa are far less than in U.S.," 2 Dec. 2020 The idea of importing the scale's natural adversary -- an Asian parasitic wasp -- has also been largely abandoned. Tristan Baurick,, "Louisiana scientists say a reviled plant could save the coast's insect-ravaged wetlands," 11 Dec. 2020 These parasitic insects lay their eggs in other animals’ nests. Theresa Machemer, Smithsonian Magazine, "In Australia, Just One Wasp Can Ground an Airplane With a Strategically Placed Nest," 1 Dec. 2020 In the new study, Adrian Smith, a zoologist at the University of Oxford, and colleagues embarked on an ambitious parasitic pilgrimage. Michael Price, Science | AAAS, "Parasitic worms found in medieval human remains hold secret for eradicating them today," 1 Sep. 2020 The snails secrete tiny parasitic flatworms into water sources. Bill Heavey, Field & Stream, "The 10 Deadliest Animals on Earth," 5 Aug. 2020 Native to tropical Africa, these big, biting flies spread the parasitic infection that causes African sleeping sickness, a disease that is 100 percent fatal without treatment, and the treatment itself is notoriously difficult. Bill Heavey, Field & Stream, "The 12 Deadliest Insects in the World," 19 Oct. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'parasitic.' 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 parasitic

1630, in the meaning defined at sense 1

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Time Traveler for parasitic

Time Traveler

The first known use of parasitic was in 1630

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Statistics for parasitic

Last Updated

15 Jan 2021

Cite this Entry

“Parasitic.” Dictionary, Merriam-Webster, Accessed 24 Jan. 2021.

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More Definitions for parasitic


How to pronounce parasitic (audio)

English Language Learners Definition of parasitic

of an animal or plant : living in or on another animal or plant and getting food or protection from it
: caused by a parasite
disapproving : getting food, money, etc., from other people without doing anything to earn it or deserve it


par·​a·​sit·​ic | \ ˌper-ə-ˈsi-tik \

Kids Definition of parasitic

: relating to or having the habit of a parasite : caused by parasites a parasitic worm parasitic diseases


par·​a·​sit·​ic | \ ˌpar-ə-ˈsit-ik How to pronounce parasitic (audio) \
variants: also parasitical \ -​i-​kəl How to pronounce parasitic (audio) \

Medical Definition of parasitic

 (Entry 1 of 2)

1 : relating to or having the habit of a parasite : living on another organism
2 : caused by or resulting from the effects of parasites

Other Words from parasitic

parasitically \ -​i-​k(ə-​)lē How to pronounce parasitic (audio) \ adverb



Medical Definition of parasitic (Entry 2 of 2)

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