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.

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Other Word Forms

• antiparasitic noun
• antiparasitical adjective
• antiparasitically adverb
• nonparasitic adjective
• nonparasitical adjective
• nonparasitically adverb
• parasitically adverb
• parasiticalness noun
• pseudoparasitic adjective
• unparasitic adjective
• unparasitical adjective
• unparasitically adverb

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."

Example Sentences

Irwin Mitchell solicitors said its clients had reported contracting gastric illnesses such as E coli, salmonella and shigella, and parasitic infections such as cryptosporidium.

From BBC • Apr. 7, 2026

Health officials are urging people not to handle lambs on farm visits this spring after an outbreak of a parasitic infection linked to farm animals last year left dozens sick.

From BBC • Mar. 24, 2026

"Ultimately, our goal is to understand how parasitic fungi contribute to -- and potentially shape -- the ocean's biogeochemical cycles, an ecosystem role that has been largely overlooked until now."

From Science Daily • Mar. 6, 2026

The spread of New World screwworm in Mexico, a parasitic fly that can infect livestock, adds another layer of uncertainty.

From Barron's • Mar. 5, 2026

Couldn’t get the redness and the swelling out of my mind, my skin responding to the invasion of parasitic bacteria.

From "Turtles All the Way Down" by John Green