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
That winter wonderland becomes a claustrophobic nightmare when an extraterrestrial shapeshifter infiltrates the base camp.
—
Huntley Woods, Entertainment Weekly, 19 Dec. 2025
The hackers will then aim to use these credentials to infiltrate an employer.
—John Kell, Fortune, 17 Dec. 2025
Dhurandhar, which follows an Indian spy who infiltrates Pakistan’s underworld to dismantle terror networks, was not cleared for release, The National reported.
—Tasneem Nashrulla, semafor.com, 15 Dec. 2025
That warning became a reality when the ISIS gunman infiltrated a Saturday meeting between Syrian forces and a handful of international coalition forces gathering to discuss ways to fight the terrorist group, according to the Interior Ministry.
—The Hill, 15 Dec. 2025
See All Example Sentences for infiltrate
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Huntley Woods, Entertainment Weekly, 19 Dec. 2025
The hackers will then aim to use these credentials to infiltrate an employer.
—John Kell, Fortune, 17 Dec. 2025
Dhurandhar, which follows an Indian spy who infiltrates Pakistan’s underworld to dismantle terror networks, was not cleared for release, The National reported.
—Tasneem Nashrulla, semafor.com, 15 Dec. 2025
That warning became a reality when the ISIS gunman infiltrated a Saturday meeting between Syrian forces and a handful of international coalition forces gathering to discuss ways to fight the terrorist group, according to the Interior Ministry.
—The Hill, 15 Dec. 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 21 Dec. 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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