infiltrate
verb
in·fil·trate
ˈin-(ˌ)fil-ˌtrāt 
in-ˈfil-
in-ˈfil-
infiltrated; infiltrating
1
: to enter or become established in gradually or unobtrusively usually for subversive purposes
The intelligence staff had been infiltrated by spies.
2
: to pass (troops) singly or in small groups through gaps in the enemy line
3
: to pass into or through (a substance) by filtering or permeating
4
: to cause (something, such as a liquid) to permeate something by penetrating its pores or interstices
: to enter, permeate, or pass through a substance or area by filtering or by insinuating gradually
infiltrate
noun
Examples of infiltrate in a Sentence
The gang was infiltrated by undercover agents.
Attempts to infiltrate undercover agents into the gang have failed.
Water can easily infiltrate the soil.
Recent Examples on the Web
Conduent, which manages critical public services across the United States, says hackers infiltrated its systems for nearly three months.
—
Kurt Knutsson, FOXNews.com, 14 Nov. 2025
The joyful color palette, spanning from pink and coral tones to desert hues and shades of blue, infiltrated also in the Alanui Finest line, the pinnacle of the brand’s offering expressed via monochrome silhouettes crafted from an exclusive cashmere and silk blend.
—Sandra Salibian, Footwear News, 13 Nov. 2025
This time the undercover cops are dispatched to infiltrate a Galician verbena orchestra, setting up a high-energy culture clash of on-stage spectacle and off-stage schemes.
—Emiliano De Pablos, Variety, 12 Nov. 2025
The hiring process has been infiltrated by fake candidates, often tied to North Korea.
—Preston Fore, Fortune, 12 Nov. 2025
See All Example Sentences for infiltrate
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Kurt Knutsson, FOXNews.com, 14 Nov. 2025
The joyful color palette, spanning from pink and coral tones to desert hues and shades of blue, infiltrated also in the Alanui Finest line, the pinnacle of the brand’s offering expressed via monochrome silhouettes crafted from an exclusive cashmere and silk blend.
—Sandra Salibian, Footwear News, 13 Nov. 2025
This time the undercover cops are dispatched to infiltrate a Galician verbena orchestra, setting up a high-energy culture clash of on-stage spectacle and off-stage schemes.
—Emiliano De Pablos, Variety, 12 Nov. 2025
The hiring process has been infiltrated by fake candidates, often tied to North Korea.
—Preston Fore, Fortune, 12 Nov. 2025
See All Example Sentences for infiltrate
Cite this Entry
“Infiltrate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infiltrate. Accessed 15 Nov. 2025.
Copy CitationKids Definition
infiltrate
verb
in·fil·trate
in-ˈfil-ˌtrāt
ˈin-(ˌ)fil-
ˈin-(ˌ)fil-
infiltrated; infiltrating
1
: to pass into or through by filtering
2
: to enter or become established gradually or secretly
Medical Definition
infiltrate
1 of 2 verb
in·fil·trate
in-ˈfil-ˌtrāt
ˈin-(ˌ)
ˈin-(ˌ)
infiltrated; infiltrating
1
: to cause (as a liquid) to permeate something by penetrating its pores or interstices
infiltrate tissue with a local anesthetic
2
: to pass into or through (a substance) by filtering or permeating
: to enter, permeate, or pass through a substance or area
infiltrate
2 of 2 noun
: something that passes or is caused to pass into or through something by permeating or filtering
especially
: a substance that passes into the bodily tissues and forms an abnormal accumulation
a lung infiltrate
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