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
Even a senator's office appears to have been infiltrated.
—
Vanessa Romo, NPR, 14 May 2026
In some areas, the guards themselves have been infiltrated or co-opted by criminal organizations.
—Antonio María Delgado, Miami Herald, 13 May 2026
Iranian Foreign Minister Abbas Araghchi is demanding the release of four Iranians detained by Kuwait, which suspects them of trying to infiltrate the Persian Gulf nation.
—Hira Humayun, CNN Money, 13 May 2026
Just when the officers come up with a plan to arrest Carter and Hakan for their respective drug empires, the kingpins start to become suspicious of their team members and become convinced that they've been infiltrated.
—Caroline Blair, PEOPLE, 12 May 2026
See All Example Sentences for infiltrate
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Vanessa Romo, NPR, 14 May 2026
In some areas, the guards themselves have been infiltrated or co-opted by criminal organizations.
—Antonio María Delgado, Miami Herald, 13 May 2026
Iranian Foreign Minister Abbas Araghchi is demanding the release of four Iranians detained by Kuwait, which suspects them of trying to infiltrate the Persian Gulf nation.
—Hira Humayun, CNN Money, 13 May 2026
Just when the officers come up with a plan to arrest Carter and Hakan for their respective drug empires, the kingpins start to become suspicious of their team members and become convinced that they've been infiltrated.
—Caroline Blair, PEOPLE, 12 May 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 18 May. 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
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