The Federal Investigation Bureau (FIB) is a law enforcement agency in the Grand Theft Auto series, based on a real life FBI aka Federal Bureau Investigation has the same role as an intelligence agency and a federal criminal investigative body. As seen in Grand Theft Auto V, they also do domestic surveillance and counterterrorism.
Franklin: Hey, is that Lester?
Michael: What
Franklin: Hey, man. What the F*** you doin' here?
Michael: You should be in Bed.
Lester: Yes. I should be, I would be if known assciates weren't busy making themselves enemies of the state.
Trevor: Woo!
Lester: FIB, Merryweather, IAA. You can F*** with them all day long.
Michael: What
Franklin: Hey, man. What the F*** you doin' here?
Michael: You should be in Bed.
Lester: Yes. I should be, I would be if known assciates weren't busy making themselves enemies of the state.
Trevor: Woo!
Lester: FIB, Merryweather, IAA. You can F*** with them all day long.
by ComedianThangs July 11, 2020

noun: a way to refer to Illinoisans that would offend your grandma if you spelled it out for her. The grandma version of FIB is flat lander.
little timmy: Holy shit, Grandma!! Look at all the God-damned FIBS on the highway today!!
Grandma: timmy!! Where'd you learn to talk like that? Never refer to them as FIBs; it's offensive. Call those bastards "flatlanders."
Grandma: timmy!! Where'd you learn to talk like that? Never refer to them as FIBs; it's offensive. Call those bastards "flatlanders."
by earpuller October 10, 2005

Fill In Boyfriend. When a bf isn't good enough or cannot satisfy his woman in one way or another (bad listener, worse lover) and another man finds himself in the bizarre position of fulfilling all her non-sexual needs.
If only he knew everything that happened in between his girlfriend and her FIB, he would know how shitty of a bf he is.
by hunglikeamoose March 10, 2009

What people from Wisconsin call people from Illinois, can mean; Fuckin' Illinois Bastard, or a nicer version; Friendy Illinios Brethren.
I went to the Milwaukee Brewers game last night... The Cubs were in town, and Miller Park was full of damn FIB's
by NickyB May 4, 2005

Fucking Illinois Bastards or Federal Investigation Bureau. Either a despective way of Winsconsin people to call Chicagoans or the FBI parody of GTA V.
by Tupamaro4Ever December 6, 2014

by ShadowMasterYT June 20, 2021

Fucking Illinois Bastard
A lame excuse for an acronym orginated by Wisconsin residents in between daily inbreeding and masturbating to portraits of Vince Lombardi.
A lame excuse for an acronym orginated by Wisconsin residents in between daily inbreeding and masturbating to portraits of Vince Lombardi.
without these FIB's contributing so heavily to our economy we would all be poor and even more WORTHLESS.
by chip douglass April 18, 2005
