1.n.One who sits in a windowless room, designed for national security intelligence work, and watches t.v and plays video games all day. This also implies that said person thinks he can get away with anything in this work place because higher ranking officials cannot get into this area with out a clearance.
2.a. used to describe the undervalued smart people who work in a scif, and see them as weird because they are too stupid to understand them.
"Wow, those scif rats really dont do shit at work and still get paid for it."
(As the scif rats are running around in their mopp gear being stupid)"Hey stop fucking around and get back to work!"
"But sir, we dont have anything to do."
"Fucking scif rats"