infiltrate

Verb
  1. Cause (a liquid) to enter by penetrating the interstices (synset 201917700)
  2. Enter a group or organization in order to spy on the members (synset 202440481)
    "The student organization was infiltrated by a traitor"
  3. Pass into or through by filtering or permeating (synset 201917525)
    "the substance infiltrated the material"
  4. Pass through an enemy line;
    In a military conflict (synset 201917356)

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