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parasitic

American  
[par-uh-sit-ik] / ˌpær əˈsɪt ɪk /
Sometimes parasitical

adjective

  1. of, relating to, or characteristic of parasites.

  2. (of diseases) due to parasites.

  3. Phonetics. excrescent.


Other Word Forms

Etymology

Origin of parasitic

1620–30; < Latin parasīticus < Greek parasītikós. See parasite, -ic

Explanation

The adjective parasitic is mainly a scientific term for talking about an organism that lives on a host, taking what it needs to stay alive while often injuring the host. By their nature, ticks, leeches, and lice are all parasitic; they live off their hosts. You can also use the word parasitic more metaphorically, to describe a person who takes without giving anything in return. A thirty year-old man who lives with his mother, eating her food and not paying rent, could be described as parasitic, since he survives by sponging off another person. Parasitic comes from the Greek word parasitos, "eating at another's table."

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Parasitic twins form when one foetus partially develops while attached to the other.

From BBC • Feb. 26, 2025

Parasitic worms, specifically soil-transmitted helminths, are common and infect roughly 25% of the global human population, according to theWorld Health Organization.

From Science Daily • Feb. 26, 2024

Parasitic roundworms are ubiquitous in the animal kingdom.

From Scientific American • Jun. 18, 2023

Parasitic populations According to a groundbreaking new study that analyzed 85 parasitic species, the majority of them suffered population declines over 140 years.

From New York Times • Jan. 12, 2023

Parasitic life, luxurious idleness, seemed impossible here; the atmosphere was too sacred, too solemn, for the fantastic ribaldry of scarlet runners, of flaunting yellow streamers.

From The Atlantic Monthly, Volume 05, No. 30, April, 1860 by Various