FBI, the /ˌef biː ˈaɪ/
(the Federal Bureau of Investigation) the police department in the US that is controlled by the central government, and that deals with crimes that break national laws rather than state laws ⇒ CIA

[TahlilGaran] Dictionary of Contemporary English ▲

FBI
Federal Bureau of Investigation
The killers were found in a nationwide search by the FBI.

[TahlilGaran] English Idioms Dictionary ▲

FBI
Famous But Incompetent (common slang used by militia groups) 
Federal Bureau of Investigation (US government) 
Female Body Inspectors  
Fidelity, Bravery, Integrity (slang for Federal Bureau of Investigation) 
Full Blooded Irish

[TahlilGaran] Acronyms and Abbreviations Dictionary ▲