in·va·sive
in-ˈvā-siv
-ziv
1
: tending to spread especially in a quick or aggressive manner: such as
a
of a non-native organism
: growing and dispersing easily usually to the detriment of native species and ecosystems
As the sheep graze, they not only eat the grass but also defoliate invasive plants …—Ann Price
It will be the second Australian insect released to thwart melaleuca, one of many exponentially spreading invasive plants that out-compete native Florida species, monopolizing wetlands and natural areas.—Neil Santaniello
Scientists say more than 150 invasive species have entered the Great Lakes, multiplying rapidly and feeding on native species or outcompeting with them for food.—Sophia Taren
b(1)
of cancer cells
: tending to infiltrate surrounding healthy tissue
… this procedure preserves the architecture of the tissue sample, which is vital for determining whether tumor cells are invasive.—Andrew A. Skolnick
(2)
of a pathogenic microorganism or disease
: disseminating from a localized area throughout the body
sepsis association with invasive bacteria
invasive streptococcal infection
2
: involving entry into the living body (as by incision or by insertion of an instrument)
invasive diagnostic techniques
3
: of, relating to, or characterized by military aggression
4
: tending to infringe
invasiveness
noun
: an organism that is not native to the place where found and tends to grow and spread easily usually to the detriment of native species and ecosystems
Zebra mussels are the latest in a series of aquatic invasives to threaten Texas' inland waters.—Shannon Tompkins
Cite this Entry
“Invasive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/invasive. Accessed 1 Sep. 2026.
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