infiltrate

[ in-fil-treyt, in-fil-treyt ]

verb (used with object)

, in·fil·trat·ed, in·fil·trat·ing.

1. to filter into or through; permeate.
2. to cause to pass in by filtering.
3. to move into (an organization, country, territory, or the like) surreptitiously and gradually, especially with hostile intent:

   The troops infiltrated the enemy lines.

4. to pass a small number of (soldiers, spies, or the like) into a territory or organization clandestinely and with hostile or subversive intent:

   The intelligence agency infiltrated three spies into the neighboring country.

verb (used without object)

, in·fil·trat·ed, in·fil·trat·ing.

1. to pass into or through a substance, place, etc., by or as by filtering.
2. Pathology. to penetrate tissue spaces or cells.

noun

1. something that infiltrates.
2. Pathology. any substance penetrating tissues or cells and forming a morbid accumulation.

infiltrate

/ ˈɪnfɪlˌtreɪt /

verb

1. to undergo or cause to undergo the process in which a fluid passes into the pores or interstices of a solid; permeate
2. military to pass undetected through (an enemy-held line or position)
3. to gain or cause to gain entrance or access surreptitiously

   they infiltrated the party structure

noun

1. something that infiltrates
2. pathol any substance that passes into and accumulates within cells, tissues, or organs
3. pathol a local anaesthetic solution injected into the tissues to cause local anaesthesia

Derived Forms

• ˈinfilˌtrator, noun
• ˈinfilˌtrative, adjective
• ˌinfilˈtration, noun

Other Words From

• in·fil·tra·tive [in, -fil-trey-tiv, in-, fil, -tr, uh, -], adjective
• in·fil·tra·tor [in, -fil-trey-ter, in-, fil, -trey-], noun
• re·in·fil·trate verb reinfiltrated reinfiltrating
• un·in·fil·trat·ed adjective

Word History and Origins

Origin of infiltrate¹

First recorded in 1750–60; in- ² + filtrate

Word History and Origins

Origin of infiltrate¹

C18: from in- ² + filtrate

Example Sentences

In 2008 Cromartie talked to The Gathering about the need to “infiltrate” secular media.

From The Daily Beast

I suppose we could infiltrate the government and do nothing.

From The Daily Beast

Police sources confirm that the Millers conspired to infiltrate an unidentified court building and execute public officials.

From The Daily Beast

North Korean special forces troops would infiltrate the devices into South Korea and use them against strategic targets.

From The Daily Beast

But she was also having daily conversations with her OSI handlers about which drug rings she should try to infiltrate.

From The Daily Beast

If it were his command hed have a sentry up there, watching for troops trying to infiltrate into the command area.

From Project Gutenberg

Was there any time when your organization drew up a list of organizations, of other organizations, that it wanted to infiltrate?

From Project Gutenberg

We had planned to infiltrate these various rightwing organizations.

From Project Gutenberg

To what extent were you able to infiltrate, as you call it, General Walker's group?

From Project Gutenberg

How did you infiltrate the Young Americans for Freedom, and what led you to believe you had been successful?

From Project Gutenberg

Related Words

• penetrate
• permeate
• pervade