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
Swalwell cut off ties to Fang in 2015, after intelligence officials briefed him and other members of Congress about Chinese efforts to infiltrate the legislative body.
—
Brittny Mejia, Los Angeles Times, 29 Mar. 2026
As reporters, our job is to infiltrate that sacred space, to barge in with notebooks and cameras and ask questions that no one wants to answer, that very often no one yet has answers for.
—Dana O’Neil, CNN Money, 28 Mar. 2026
Still, Handala caused some chaos earlier this month after infiltrating US medical equipment provider Stryker and launching a data-wiping attack that affected tens of thousands of devices, including employee phones.
—Michael Kan, PC Magazine, 27 Mar. 2026
In 2024 Israeli operatives infiltrated Hezbollah’s supply chain and used shell companies to sell members pagers and walkie-talkies rigged with explosives.
—Deni Ellis Béchard, Scientific American, 26 Mar. 2026
See All Example Sentences for infiltrate
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Brittny Mejia, Los Angeles Times, 29 Mar. 2026
As reporters, our job is to infiltrate that sacred space, to barge in with notebooks and cameras and ask questions that no one wants to answer, that very often no one yet has answers for.
—Dana O’Neil, CNN Money, 28 Mar. 2026
Still, Handala caused some chaos earlier this month after infiltrating US medical equipment provider Stryker and launching a data-wiping attack that affected tens of thousands of devices, including employee phones.
—Michael Kan, PC Magazine, 27 Mar. 2026
In 2024 Israeli operatives infiltrated Hezbollah’s supply chain and used shell companies to sell members pagers and walkie-talkies rigged with explosives.
—Deni Ellis Béchard, Scientific American, 26 Mar. 2026
See All Example Sentences for infiltrate
Cite this Entry
“Infiltrate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infiltrate. Accessed 31 Mar. 2026.
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
Love words? Need even more definitions?
Merriam-Webster unabridged
