infiltrate

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

verb (used with object)

infiltrated, infiltrating 

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)

infiltrated, infiltrating 

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

Other Word Forms

• infiltrative adjective
• infiltrator noun
• reinfiltrate verb
• uninfiltrated adjective
• infiltration noun

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

The plan is facing lawsuits from homeowners in Altadena, Pacific Palisades and nearby communities who allege the plan is refusing to properly test and remediate homes that were infiltrated by smoke, soot and ash.

From Los Angeles Times

Tout gangs infiltrated the ticket exchange last season.

From BBC

In a common process, the "initial access broker" sold the Kido access to Radiant, which went on to further infiltrate Kido's systems and steal the data.

From BBC

Posing as a dog fighter, the BBC was able to infiltrate online platforms and win the trust of members of the wider European network.

From BBC

Syn estimated that their team could demand a ransom in the tens of millions if they successfully infiltrated the corporation.

From BBC

Related Words

• penetrate 
• permeate 
• pervade