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infiltration

UK/ɪnfɪlˈtɹeɪʃən/US/ˌɪnfəlˈtɹeɪʃən/
nounC1Occasional — familiar, but not everyday · #9,168 of 15,258leans written

Other forms: infiltrations

Infiltration is the entering of a group or a place secretly. Police infiltration, infiltration of the union, guard against infiltration.

The secrecy is the whole word: infiltration means joining in order to report back. Police infiltration of protest groups has produced serious scandals in Britain, where officers formed relationships under false identities. In medicine it means fluid spreading into tissue.

Definitions of infiltration

  1. 1nouninfiltrationThe entering of a group or a place secretly.C1

    “The rebels planned their infiltration of the city at night, dressed as farmers.”

infiltration is an entering.

Where it comes from

Medieval Latin infiltratio, from in plus filtrare, to filter, from a Germanic word for felt.

  1. Medieval Latin

    infiltrātiōnem

  2. Middle English

    infiltracioun

  3. English, today

    infiltration

From Middle English infiltracioun, from Medieval Latin infiltrātiōnem, infiltrātiō. by surface analysis, infiltrat(e) + infiltrate + ion.

Etymology from Wiktionary, CC BY-SA

Practise this word

infiltration in the wild

  • The infiltration capacity is defined as the maximum rate of infiltration.

    Infiltration (hydrology)

  • The infiltration capacity decreases as the soil moisture content of soils surface layers increases.

    Infiltration (hydrology)

  • Infiltration may refer to normal physiological processes, such as the infiltration of certain immune cells into peripheral tissues.

    Infiltration (medical)

  • The second was held on 7 June on a popular initiative "against foreign infiltration", and was rejected by voters.

    1970 Swiss referendums

From Wikipedia, CC BY-SA 4.0. These sentences were written by other people about their own subjects; they are here to show the word at work, not as anybody’s opinion.