- 1[transitive, intransitive] to enter or make someone enter a place or an organization secretly, especially in order to get information that can be used against it infiltrate something The headquarters had been infiltrated by enemy spies. infiltrate somebody into something Rebel forces were infiltrated into the country. infiltrate into something The CIA agents successfully infiltrated into the terrorist organizations.
- 2[intransitive, transitive] infiltrate (into) something (technology) (especially of liquids or gases) to pass slowly into something Only a small amount of the rainwater actually infiltrates into the soil.
NAmE//ˈɪnfɪlˌtreɪt//, NAmE//ɪnˈfɪltreɪt//Verb Forms present simple I / you / we / they infiltrate
he / she / it infiltrates
past simple infiltrated
-ing form infiltrating
infiltrationjump to other results
NAmE//ˌɪnfɪlˈtreɪʃn//noun [uncountable] the infiltration of terrorists from across the border the infiltration of rain into the soil