infiltrate
in- + filtrate
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source: [プラスティック・メモリーズのアイラと海松エルが潜入工作をするGIF画像｜無料GIF画像検索 GIFMAGAZINE 646782]
verb with object
1. enter or gain access to (an organization, place, etc.) surreptitiously and gradually, especially in order to acquire secret information:
〈スパイなどが〉〈組織など〉に潜入する; «…に» 〈スパイなど〉を潜入させる «into»
e.g. other areas of the establishment were infiltrated by fascists.
permeate or become a part of (something) by infiltration:
｟しばしば非難して｠ 〈物･考えなど〉を普及させる
e.g. computing has infiltrated most professions now.
Medicine (of a tumor, cells, etc.) spread into or invade (a tissue or organ).
2. (of a liquid) permeate (something) by filtration:
…に浸透する, しみ通る
e.g. virtually no water infiltrates deserts such as the Sahara.
introduce (a liquid) into something by filtration:
e.g. lignocaine was infiltrated into the wound.
noun Medicine
an infiltrating substance or a number of infiltrating cells.
DERIVATIVES
infiltrator |ˈinfilˌtrādər| noun
ORIGIN
Middle English (as infiltration): from in-2 + filtrate.