- 1[transitive, intransitive] to go into or through something penetrate something The knife had penetrated his chest. The sun's radiation penetrates the skin. The cold seemed to penetrate his bones. (figurative) The war penetrates every area of the nation's life. penetrate into/through/to something These fine particles penetrate deep into the lungs.
- 2[transitive, intransitive] to succeed in entering or joining an organization, a group, etc. especially when this is difficult to do penetrate something They had penetrated airport security. The party has been penetrated by extremists. This year the company has been trying to penetrate new markets (= to start selling their products there). penetrate into something The troops had penetrated deep into enemy lines.
- 3[transitive] penetrate something to see or show a way into or through something Our eyes could not penetrate the darkness. The flashlights barely penetrated the gloom. narrow alleys where the sun never penetrates
- 4 [transitive] penetrate something to understand or discover something that is difficult to understand or is hidden Science can penetrate many of nature's mysteries. a style that is difficult to penetrate No one could penetrate the meaning of the inscription.
- 5 [intransitive, transitive] to be understood or realized by someone I was at the door before his words penetrated. penetrate something None of my advice seems to have penetrated his thick skull (= he has not listened to any of it).
NAmE//ˈpɛnəˌtreɪt//Verb Forms present simple I / you / we / they penetrate
he / she / it penetrates
past simple penetrated
-ing form penetrating