infiltrate

verb

in·​fil·​trate ˈin-(ˌ)fil-ˌtrāt How to pronounce infiltrate (audio) in-ˈfil- How to pronounce infiltrate (audio)
infiltrated; infiltrating

transitive verb

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

intransitive verb

: to enter, permeate, or pass through a substance or area by filtering or by insinuating gradually
infiltrate noun
infiltration noun
infiltrative
ˈin-(ˌ)fil-ˌtrā-tiv How to pronounce infiltrate (audio)
in-ˈfil-trə-
adjective

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 The Israeli team was the target of the deadliest terror attack in Olympic history in 1972, when eight Palestinian militants infiltrated the Olympic Village in Munich, resulting in the deaths of six coaches and five athletes. Kevin Baxter, Los Angeles Times, 16 July 2024 He was circumvented by a United States undercover police officer who infiltrated the online chat and reported Plumb’s posts to the FBI, according to The Guardian. Alyssa Goldberg, USA TODAY, 12 July 2024 Union soldiers dressed as civilians infiltrated the Confederacy, hijacked a train and drove it north for 87 miles, destroying Confederate infrastructure along the way. Kathryn Watson, CBS News, 3 July 2024 Now, courts will get to decide how much deference to give regulators’ decisions—and the same conservative legal movement that led to the Supreme Court’s decisions over the past week has infiltrated lower courts as well. Jordan Pearson, WIRED, 1 July 2024 See all Example Sentences for infiltrate 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'infiltrate.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1758, in the meaning defined at transitive sense 4

Time Traveler
The first known use of infiltrate was in 1758

Dictionary Entries Near infiltrate

Cite this Entry

“Infiltrate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infiltrate. Accessed 24 Jul. 2024.

Kids Definition

infiltrate

verb
in·​fil·​trate in-ˈfil-ˌtrāt How to pronounce infiltrate (audio) ˈin-(ˌ)fil- How to pronounce infiltrate (audio)
infiltrated; infiltrating
1
: to pass into or through by filtering
2
: to enter or become established gradually or secretly
infiltration noun

Medical Definition

infiltrate

1 of 2 verb
in·​fil·​trate in-ˈfil-ˌtrāt How to pronounce infiltrate (audio) ˈin-(ˌ) How to pronounce infiltrate (audio)
infiltrated; infiltrating

transitive verb

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

intransitive verb

: 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

More from Merriam-Webster on infiltrate

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!