par·​a·​sit·​ic ˌper-ə-ˈsi-tik How to pronounce parasitic (audio)
variants or less commonly parasitical
: of, relating to, or being a parasite: such as
: 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
: caused by or resulting from the effects of parasites
a parasitic disease/infection
of a bird : laying eggs in the nest of another bird
The cowbird and the cuckoo are parasitic birds.
: 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
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.
parasitically 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 The most common side effects of Xolair are injection site reactions and fever, but the FDA noted that the drug has also been associated with joint pain, rash, parasitic infections, malignancies and abnormal laboratory tests. Jonel Aleccia, Quartz, 16 Feb. 2024 Author Chen, however, suggested that unwanted electronic characteristics, particularly a weakness called parasitic inductance, would plague transistors that are simply packaged together rather than integrated. IEEE Spectrum, 16 Jan. 2024 Some common reasons for claim denials include: Treatments for parasitic conditions: Many insurers will deny treatment for parasitic conditions, such as heartworms, even if your pet was on preventive medications. Kat Tretina,, 8 Jan. 2024 The plot centers around a motivational speaker who becomes infected with a parasitic demon called the Sanshi from her home country of Vietnam. Erin Couch, The Enquirer, 2 Jan. 2024 This parasitic fungus is a real example of one (kind of). Katie Liu, Discover Magazine, 14 Dec. 2023 He was treated for mange [a skin disease caused by parasitic mites]. Erin Clements, Peoplemag, 1 Dec. 2023 But this is too parasitic a term to apply to the artfulness occurring in the Newman. Thomas Floyd, Washington Post, 11 Dec. 2023 Such an event is likely the result of viral, bacterial, or parasitic infection, or blockage in the appendix, an intestinal tube. Dennis Romero, NBC News, 12 Dec. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'parasitic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1630, in the meaning defined at sense 1

Time Traveler
The first known use of parasitic was in 1630

Dictionary Entries Near parasitic

Cite this Entry

“Parasitic.” Dictionary, Merriam-Webster, Accessed 23 Feb. 2024.

Kids Definition


: of or relating to parasites or their way of life : being a parasite

Medical Definition


1 of 2 adjective
par·​a·​sit·​ic ˌpar-ə-ˈsit-ik How to pronounce parasitic (audio)
variants also parasitical
: relating to or having the habit of a parasite : living on another organism
: caused by or resulting from the effects of parasites
parasitically adverb


2 of 2 noun
Last Updated: - Updated example sentences
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