infiltrate

If you infiltrate a group or organization, you join it in order to gain information, like an employee of a donut shop that infiltrates the competition to try to learn its "secret recipe" for its delicious dough.

Infiltrate is a verb that is familiar to international spies and undercover agents, who are all adept at joining a group under false pretenses, fitting in, and working their way up to the highest ranks in order to find out as much information as they can about the group. The word can be used more broadly to describe anything that stealthily becomes a part of something else, such as slang words that infiltrate our everyday speech.

Definitions of infiltrate
  1. verb
    pass through an enemy line; in a military conflict
    synonyms: pass through
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    type of:
    go across, go through, pass
    go across or through
  2. verb
    enter a group or organization in order to spy on the members
    “The student organization was infiltrated by a traitor”
    synonyms: penetrate
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    type of:
    fall in, get together, join
    become part of; become a member of a group or organization
  3. verb
    cause (a liquid) to enter by penetrating the interstices
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    type of:
    filter, percolate, permeate, sink in
    pass through
  4. verb
    pass into or through by filtering or permeating
    “the substance infiltrated the material”
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    type of:
    filter, percolate, permeate, sink in
    pass through
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