acronym for FUCKING IDIOT LIAR. A person who openly makes up stories and lies to you, but is ridiculously idiotic and so doesn't understand your superior intellect knows he is lying to you.
FIL - yeah bro, I want to discover black matter, I'm way into physics.
smart guy - I think you mean 'dark matter'
FIL - yeah, thats what I'm talking about, black matter. Dude I got my masters in Physics, I'm brilliant!
smart guy- wow, I think I need to go.