infiltrator

American  

[in-fil-trey-ter, in-fil-trey-] / ˈɪn fɪlˌtreɪ tər, ɪnˈfɪl treɪ- /

noun

1. a soldier, intelligence agent, or other person who moves surreptitiously and gradually into an organization, territory, community, or the like, especially with hostile intent.

   Using a false name, the infiltrator participated in meetings and prep sessions with the protest group and had complete access to their documentation.

2. a person or thing that causes one substance to pass into another by filtering.

   The roots of wetland plants serve as massive water infiltrators, allowing more rainwater to seep into the soil and recharge underground aquifers.

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Etymology

Origin of infiltrator

infiltrat(e) ( def. ) + -or ² ( def. )

Example Sentences

Although it has been widely alleged - by politicians, police and protesters - that organised groups and infiltrators acting on behalf of political interests helped drive the destruction, we have found no evidence to substantiate the claim.

From BBC

Hoover-style service resumed, in other words, with a new target even more universally reviled than Red infiltrators.

From Salon

"Be careful, the enemy is losing in every direction," he added, telling them that this meant they were more likely to be on alert for infiltrators and spies.

From BBC

"Some infiltrators into the revolution, some saboteurs, and some weak-minded people are taking advantage of the situation in the areas that were recently liberated," he says.

From BBC

She details evidence gained through wiretaps, police infiltrators and witnesses – some of which her office has made public.

From BBC

Related Words

• spy