Definition of infiltrate in English:


Line breaks: in|fil|trate
Pronunciation: /ˈɪnfɪltreɪt


[with object]
  • 1Enter or gain access to (an organization, place, etc.) surreptitiously and gradually, especially in order to acquire secret information: the organization has been infiltrated by informers
    More example sentences
    • This is why I sometimes think we should infiltrate the Countryside Alliance - we'd get more cameras pointed at us then…
    • Now that we have a common picture of the communications architecture, we must discuss using information to successfully infiltrate an enemy's position.
    • He said intelligence agents and police informers had infiltrated villages in the area and worked as drivers, masons and hawkers for months to gather information about Veerappan and his men who were suspected to be hiding nearby.
  • 1.1Introduce (someone) into an organization, place, etc. surreptitiously, in order for them to acquire secret information: they infiltrated an agent into the factory
    More example sentences
    • Phil continues to work on Nigel, trying to infiltrate him into a terrorist gang he believes is centered at a local mosque.
    • Make sure you have good radio contact with the forward observer and somehow get him into a putting him on a nearby hill, or it can mean infiltrating him in prior to the attack.
    • He was infiltrated back into South Africa as one of the commanders of Operation Vula, with a mission to build viable underground and military structures.
  • 1.2 Medicine (Of a tumour, cells, etc.) spread into or invade (a tissue or organ): one of the tumours infiltrated the submucosa
    More example sentences
    • In this specimen, large lymphoid cells diffusely infiltrated muscle and fibrous tissue.
    • The surrounding stroma was infiltrated by plasma cells and scattered aggregates of lymphocytes, forming follicles with germinal centres.
    • Tumor cells also infiltrated the smooth muscle of the ciliary body.
  • 3Gradually permeate or become a part of: computing has infiltrated most professions now
    More example sentences
    • It reads like a blog, but you only have to look at a couple of the images to know this is a commercially popular side of US culture and quickly infiltrating ours.
    • Postmodernists claim that science, no less than religion and literature and philosophy, is infiltrated with culture.
    • The ensuing Meiji policy of modernization allowed Western ideas, institutions, and culture to infiltrate Japan.


Medicine Back to top  
  • An infiltrating substance or a number of infiltrating cells: a chest radiograph revealed a patchy infiltrate in the left lower lobes
    More example sentences
    • His follow-up radiograph 10 days after the initiation of prednisone showed a substantial decrease of the infiltrate.
    • The bone marrow was replaced by an infiltrate of blast cells with medium-sized nuclei, multiple nucleoli, and moderate amounts of cytoplasm.
    • Although the chest radiograph may be normal initially, subsequent radiographs will reveal an infiltrate, which may extend rapidly, involving one or more lobes as well as the pleura.



Pronunciation: /-ˈtreɪʃ(ə)n/
More example sentences
  • Any large organization is inherently vulnerable to espionage and infiltration.
  • Another source of concern is terrorist infiltration of our intelligence agencies.
  • Overt violence now gives way to a conflict based on espionage and infiltration.


More example sentences
  • There was a keen awareness of the possibility of infiltrators and informers; people who turned up in Sudan and later Afghanistan were rigorously vetted.
  • He laid most of the blame for Friday's violence on infiltrators from the National Intelligence Service.
  • Apparently, Ray and Ribeiro went ahead with their undercover operations, using informers and infiltrators from the underworld.
spy, agent, secret agent, undercover agent, operative, plant, intruder, interloper, subversive, informant, informer, mole, entrist, entryist
informal gatecrasher
North American informal spook
archaic intelligencer


Middle English (as infiltration): from in-2 + filtrate.

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