Definition of infiltrate
1 : to cause (something, such as a liquid) to permeate something by penetrating its pores or interstices
2 : to pass into or through (a substance) by filtering or permeating
3 : to pass (troops) singly or in small groups through gaps in the enemy line
4 : to enter or become established in gradually or unobtrusively usually for subversive purposes the intelligence staff had been infiltrated by spies
: to enter, permeate, or pass through a substance or area by filtering or by insinuating gradually
infiltrationplay \ˌin-(ˌ)fil-ˈtrā-shən\ noun
infiltrativeplay \ˈin-(ˌ)fil-ˌtrā-tiv, 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 of infiltrate from the Web
Undercover officers infiltrated Agnello's business beginning in 2013, and investigators used wiretaps to monitor Agnello's communications with Mafia contacts back in New York, prosecutors said.
Hackers appeared to infiltrate payment data systems with malicious code that was undetectable by existing antivirus systems, Howard Riefs, a spokesman for Sears Holdings, told NBC News.
By using glass as a curtain wall, natural light can infiltrate further into the building, as was obvious to everyone in attendance at the ribbon-cutting.
These storylines can infiltrate schools, tainting a teacher’s expectations of both her power and her complicated students—like T, my 10th-grader who toted a pink teddy bear with a safety pin jammed through its ear.
IS also slowly infiltrated the city as fighters from countries like Mali, Tunisia, Egypt and Syria moved in and later declared Sirte an IS emirate.
On February 19, TigerSwan makes explicit its plans to infiltrate a Chicago protest group.
Every once in a while Mr. Zorn, the alto saxophonist and experimental music figurehead, infiltrates the Vanguard, straight-ahead jazz’s temple, for a one-off matinee show.
As Doom became more popular, my friends and I noticed several Ferraris had infiltrated our once pickup-truck-only city.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'infiltrate'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
First Known Use of infiltrate
INFILTRATE Defined for English Language Learners
Definition of infiltrate for English Language Learners
: to secretly enter or join (something, such as a group or an organization) in order to get information or do harm
: to cause (someone) to secretly enter or join a group, organization, etc.
: to pass into or through (something)
Medical Definition of infiltrate
transitive verb: 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
Medical Definition of infiltrate
: 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
Seen and Heard
What made you want to look up infiltrate? Please tell us where you read or heard it (including the quote, if possible).