MI5


Meaning of MI5 in English

MI5 /ˌem aɪ ˈfaɪv/ BrE AmE noun

a secret British government organization whose job is to keep Britain safe from attack by enemies inside the country, such as foreign SPIES or ↑ terrorist s :

a government agent working for MI5

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.