F.O.S 

Full Of Shit: no data, no proof, a baseless opinion.

He's F.O.S. He doesn't know what he's talking about.

F.O.S by gmerritt November 16, 2005

F.O.S 

term used for masturbation. Stands for "Fuck Ones Self"

Going to bed to FOS be back later

F.O.S by toilet`duck January 1, 2005

F.O.S 

iykyk

Hold on, Ill be F.O.S soon.

F.O.S by Keep in check August 7, 2024

F.O.S. 

Abreviation for "Full of Shit"

You are so "F.O.S."
They are really so "F.O.S."

F.O.S. by Bev Lane June 2, 2006

F.O.S. 

Code word for full of shit to get you out of trouble. You say it to someone and they just look confused when other people might realize what it means. Can also be pronounced Fos for short.

When my teacher told me that my homework assignment I turned in was worth a D when I knew it was worth and A, I said "You're F.O.S., this work is flawless!" I got sent to the office because apparently he knew what F.O.S. meant.

F.O.S. by PrincessR December 7, 2009

F.O.S. 

Acronym for Fuck On Sight. A type of individual when seen by another, one would be willing to have sex with without knowing anything about them, not even their name.

"Dude, that girl in the parking lot, her eyes, those hips, she's a definite F.O.S."

F.O.S. by mayej May 10, 2009

F.O.S. 

Flowers over snitchs, found in a lil wayne song

F.O.S. for life!
F.O.S. all day

F.O.S. by BALLIN!! January 6, 2008