Meanings
present singular third person infiltrates · participle present infiltrating · participle past infiltrated · past infiltrated
- ambitransitiveTo surreptitiously penetrate, enter or gain access to.
The spy infiltrated the high-tech company and stole many secrets.
1 more example
Caithness was infiltrated with a palpable sense of being underimagined.
2012, Will Self, Tough, Tough Toys for Tough, Tough Boys, →ISBN, page 113 - transitiveTo cause to penetrate in this way.
The agency infiltrated several spies into the company.
- ambitransitiveTo pass through something by filtration.
- transitiveTo cause (a liquid) to pass through something by filtration.
- ambitransitivemedicineTo invade or penetrate a tissue or organ.
High-grade tumors often infiltrate surrounding structures.
2 more examples
In certain conditions, immune cells may infiltrate into the cerebrospinal fluid.
Plesner et al. reported the nonbeta islet endocrine cell remodeling in diabetic NOD mice: that study suggested that infiltrating immune cells may restrict alpha-cell expansion in NOD mouse islet in the diabetic state [ 36 ].
2015 August 5, Roberto Codella et al., “Moderate Intensity Training Impact on the Inflammatory Status and Glycemic Profiles in NOD Mice”, in Journal of Diabetes Research, volume 2015, →DOI - transitivegovernmentTo send (soldiers, spies, etc.) through gaps in the enemy line.
Antonyms: exfiltrate
- intransitiveTo move from a vein, remaining in the body.
plural infiltrates
- medicineAny undesirable substance or group of cells that has made its way into part of the body.
One critical distinction to make is whether a focal corneal infiltrate is infected with bacteria or is a sterile immunologic response.
2008, Jimmy D. Bartlett, Siret D. Jaanus, Clinical Ocular Pharmacology, page 5392 more examples
Extensive lumpy infiltrates with a tendency to caseate and to form fistulas with purulent secretions appear, mainly in the anogenital region.
2013, Otto Braun-Falco, Dermatology, page 141Common immunohistochemical markers of this lymphoma include CD2, CD56, CD3, and T-cell receptors. 7 Typically, the histology of these lymphomas are characterized by monomorphic inflammatory cellular infiltrates, which may be diffuse or show angiocentricity and angiodestruction as well as tissue destruction. 7 Lymphoid markers from the nasal mucosal biopsy from this patient were negative for CD56 and EBER.
2015, Brook McConnell, M. Sherif Said, Vijay R. Ramakrishnan, “Nasal septal perforation associated with pyoderma gangrenosum”, in Allergy & Rhinology, volume 6, →DOI
Synonyms & antonyms
verbTo send (soldiers, spies, etc.) through gaps in the enemy line.
More synonyms by meaning
verbenter a group or organization in order to spy on the members
Synonym sets from Open English WordNet, CC BY 4.0.
Origin
- Medieval Latininfiltrātus
- Middle Englishinfiltrate
- Englishinfiltrate
From Middle English infiltrate (adjective), from Medieval Latin infiltrātus, from infiltrō.
More words from Middle English, Medieval Latin
Full word history & related roots →Translations
Afrikaans infiltreer
- infiltreerto surreptitiously penetrate, enter or gain access
Bulgarian процеждам, просмуквам се
- процеждам (proceždam)to cause a fluid to pass through a substance by filtration
- просмуквам се (prosmukvam se)to cause a fluid to pass through a substance by filtration
Catalan infiltrar, infiltrar
- infiltrarto surreptitiously penetrate, enter or gain access
- infiltrarto cause a fluid to pass through a substance by filtration
Czech proniknout
- proniknoutto surreptitiously penetrate, enter or gain access
Esperanto infiltri
- infiltrito surreptitiously penetrate, enter or gain access
Finnish soluttautua, soluttaa
- soluttautuato surreptitiously penetrate, enter or gain access
- soluttaato send soldiers through gaps in the enemy line
- suodattaato cause a fluid to pass through a substance by filtration
French infiltrer
- infiltrerto surreptitiously penetrate, enter or gain access
German infiltrieren, unterwandern
- infiltrierento surreptitiously penetrate, enter or gain access
- unterwandernto surreptitiously penetrate, enter or gain access
- Infiltratinfiltrate
Greek διεισδύω
- διεισδύω (dieisdýo)to surreptitiously penetrate, enter or gain access
Hindi घुसपैठ करना, पैठना
- घुसपैठ करना (ghuspaiṭh karnā)to surreptitiously penetrate, enter or gain access
- पैठना (paiṭhnā)to surreptitiously penetrate, enter or gain access
Hungarian beszivárog, infiltrátum
- beszivárogto surreptitiously penetrate, enter or gain access
- infiltrátuminfiltrate
- beszűrődésinfiltrate
Indonesian infiltrat
- infiltratinfiltrate
Irish insíothlaigh, síothlaigh isteach
- insíothlaighto surreptitiously penetrate, enter or gain access
- síothlaigh isteachto surreptitiously penetrate, enter or gain access
- insíothlaighto cause a fluid to pass through a substance by filtration
- síothlaigh isteachto cause a fluid to pass through a substance by filtration
Italian infiltrare, infiltrare
- infiltrareto surreptitiously penetrate, enter or gain access
- infiltrareto send soldiers through gaps in the enemy line
- filtrareto cause a fluid to pass through a substance by filtration
Japanese 潜入する, 潜入させる
- 潜入する (sennyū suru)to surreptitiously penetrate, enter or gain access
- 潜入させる (sennyū saseru)to send soldiers through gaps in the enemy line
- 浸透させる (shintō saseru)to cause a fluid to pass through a substance by filtration
Māori ngoto
- ngototo surreptitiously penetrate, enter or gain access
Persian نفوذ کردن
- نفوذ کردن (nofuz kardan)to surreptitiously penetrate, enter or gain access
Polish infiltrować, zinfiltrować
- infiltrowaćto surreptitiously penetrate, enter or gain access
- zinfiltrowaćto surreptitiously penetrate, enter or gain access
- infiltrowaćto send soldiers through gaps in the enemy line
- zinfiltrowaćto send soldiers through gaps in the enemy line
- infiltrowaćmove from a vein
- zinfiltrowaćmove from a vein
- przesączaćto cause a fluid to pass through a substance by filtration
- przesączyćto cause a fluid to pass through a substance by filtration
- naciekinfiltrate
Romanian infiltrat
- infiltratinfiltrate
Russian проса́чиваться, просочи́ться
- проса́чиваться (prosáčivatʹsja)to surreptitiously penetrate, enter or gain access
- просочи́ться (prosočítʹsja)to surreptitiously penetrate, enter or gain access
- проника́ть (pronikátʹ)to surreptitiously penetrate, enter or gain access
- прони́кнуть (proníknutʹ)to surreptitiously penetrate, enter or gain access
- проникать в тыл противника (pronikatʹ v tyl protivnika)to send soldiers through gaps in the enemy line
- проникнуть в тыл противника (proniknutʹ v tyl protivnika)to send soldiers through gaps in the enemy line
Spanish infiltrarse, infiltrar
- infiltrarseto surreptitiously penetrate, enter or gain access
- infiltrarto cause a fluid to pass through a substance by filtration
Swedish infiltrera
- infiltrerato surreptitiously penetrate, enter or gain access
Thai แทรกซึม, สอดแทรก
- แทรกซึมto surreptitiously penetrate, enter or gain access
- สอดแทรกto send soldiers through gaps in the enemy line
Turkish süzmek
- süzmekto cause a fluid to pass through a substance by filtration
Cite this entry
infiltrate. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/infiltrate
“infiltrate.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/infiltrate. Accessed November 4, 2026.
WatkinsX Dictionary, s.v. “infiltrate,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/infiltrate.
Source: infiltrate on Wiktionary, CC BY-SA 4.0.