Answer: infiltrates

AnswerCrossword Clue
infiltratesEnter or gain access to (an organization, place, etc.) surreptitiously and gradually, esp. in order to acquire secret information
infiltratesIntroduce (a liquid) into something in this way
infiltratesPermeate or become a part of (something) in this way
infiltrates(of a tumor, cells, etc.) Spread into or invade (a tissue or organ)
infiltratesINFILTRATE, to cause to filter into
infiltrates(of a liquid) Permeate (something) by filtration