From Longman Dictionary of Contemporary Englishinfiltratein‧fil‧trate /ˈɪnfɪltreɪt $ ɪnˈfɪltreɪt, ˈɪnfɪl-/ verb 1 [intransitive always + adverb/preposition, transitive]JOIN AN ORGANIZATIONSPY to secretly join an organization or enter a place in order to find out information about it or harm it Police attempts to infiltrate neo-Nazi groups were largely unsuccessful.infiltrate into Rebel forces have been infiltrating into the country.2 [transitive] to secretly put people into an organization or place in order to find out information or to harm itinfiltrate somebody into something They repeatedly tried to infiltrate assassins into the palace.3 [transitive] to become a part of something – used especially to show disapproval Commercialism has been infiltrating universities for the past decade. —infiltrator noun [countable] —infiltration /ˌɪnfɪlˈtreɪʃən/ noun [uncountable]→ See Verb table
Examples from the Corpus
infiltrate• Federal undercover agents infiltrated a Miami drug ring.• Everyone knew the organization had been infiltrated by government agents, but could not prove it.• Police attempts to infiltrate neo-Nazi groups have been largely unsuccessful.• The Communists effectively infiltrated the government and the political parties.infiltrate into• Intelligence reports confirm that terrorists have infiltrated into the region.infiltrate somebody into something• They repeatedly tried to infiltrate assassins into the palace. 