infiltrate
C1Formal, academic, journalistic, technical (esp. military, political, medical, security).
Definition
Meaning
To secretly or gradually enter or gain access to a place, organisation, or system, especially with hostile intent or to obtain information.
1) (Medical/Biology) To pass into or through a substance, tissue, or area by filtering or permeating. 2) (General) To become gradually or subtly established in a place or group over time.
Linguistics
Semantic Notes
The term inherently suggests covert, gradual, and often subversive action. It implies overcoming some form of boundary or resistance. It can be used both transitively ('to infiltrate an organisation') and intransitively ('the water infiltrated').
Dialectal Variation
British vs American Usage
Differences
No significant difference in core meaning. Spelling and verb conjugation follow standard UK/US conventions (e.g., infiltrated vs. infiltrated).
Connotations
Slightly more common in UK press regarding political or protest groups; in US media, often linked to cybersecurity, intelligence, and counter-terrorism contexts.
Frequency
Comparatively high frequency in both varieties due to its use in political and security discourse.
Vocabulary
Collocations
Grammar
Valency Patterns
[SVO] They infiltrated the group.[SVOA] Agents infiltrated weapons across the border.[SV] Water can easily infiltrate through the cracks.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “A fifth column (refers to infiltrators working from within)”
- “A mole in the organisation”
Usage
Context Usage
Business
Used negatively: 'We must prevent competitors from infiltrating our supply chain.' or positively in marketing: 'Our product aims to infiltrate new market segments.'
Academic
Common in political science, history, and sociology texts describing subversion, espionage, or social movements. Also in medicine/biology: 'Lymphocytes infiltrate the infected tissue.'
Everyday
Rare in casual conversation. Might be used metaphorically: 'His new ideas are starting to infiltrate the team's thinking.'
Technical
Military/Intelligence: Covert entry. Medicine: Movement of cells or fluid into tissue. Geology/Hydrology: Process of water entering the ground.
Examples
By Part of Speech
verb
British English
- Undercover officers managed to infiltrate the criminal gang.
- Damp had begun to infiltrate the old basement walls.
American English
- The agency worked to infiltrate the terrorist cell.
- The software is designed to infiltrate secure networks.
adverb
British English
- The cells spread infiltratively through the tissue. (Rare, technical)
- The ideology was adopted infiltratively over decades. (Very rare)
American English
- The tumor grew infiltratively. (Medical)
- The propaganda worked infiltratively. (Very rare)
adjective
British English
- The infiltrative nature of the cancer made surgery difficult.
- They faced an infiltrative threat from across the border.
American English
- The biopsy showed an infiltrative pattern.
- The report detailed the group's infiltrative tactics.
Examples
By CEFR Level
- The spy tried to infiltrate the enemy camp.
- Water can infiltrate the soil after heavy rain.
- The journalist infiltrated the organisation to expose its activities.
- Authorities fear extremist groups are attempting to infiltrate the protest movement.
- The new management's ethos gradually infiltrated every department, changing the corporate culture.
- The biopsy confirmed that malignant cells had infiltrated the surrounding connective tissue.
Learning
Memory Aids
Mnemonic
Think of a FILTER. To IN-FILTER-ATE is to move *into* something as if through a filter—slowly, particle by particle, and often unnoticed.
Conceptual Metaphor
LIQUID SECRETLY ENTERING A SOLID (Ideas infiltrate minds; spies infiltrate organisations; water infiltrates soil). INVASION AS A DISEASE (The corrupting influence infiltrated the institution).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid directly translating as 'фильтровать' (to filter). The correct conceptual equivalents are 'внедряться', 'проникать (тайно)', 'инфильтрировать(ся)' (medical).
- Do not confuse with 'inflict' (наносить ущерб).
Common Mistakes
- Using it without the sense of secrecy/gradualness: *'He infiltrated the room loudly.' (Incorrect) -> 'He entered/barged into the room loudly.'
- Confusing 'infiltrate' (enter) with 'exfiltrate' (leave secretly).
Practice
Quiz
In which context is the use of 'infiltrate' LEAST appropriate?
FAQ
Frequently Asked Questions
Rarely. Its core meaning involves secrecy and often hostile intent, so it's typically negative or neutral. A positive spin might be in marketing: 'to infiltrate the market' meaning to gain a foothold.
The primary noun is 'infiltration'. A person who infiltrates is an 'infiltrator'.
No. It is commonly used for liquids, gases, ideas, and cells (e.g., 'The dye infiltrated the fabric', 'Western culture infiltrated the region').
'Infiltrate' focuses on the *act of entering* secretly or through barriers. 'Permeate' focuses on the result of being *spread throughout* every part of something. You infiltrate to then permeate.