undercover fat

Someone who doesn't look fat while clothed, but secretly hides a gut

I had a locker next to that kid in gym class in high school, and trust me, he's undercover fat.

She looks hot at first, but she's just an undercover fat girl hiding beneath that sweatshirt

by RC-Cola December 21, 2005

Undercover Fatty

Also known as UCF, this refers to a girl who takes the correct angles in social media pictures in order for you to never find out what she looks like upon first meeting.

I met this girl on Bumble but I really can't tell from the photo angles what she looks like... other than her face, I really just hope she's not a UCF (undercover fatty).

by sSupreme December 18, 2017

Undercover Fatass

Somebody who, despite being extremely skinny, eats constantly and always speaks of being hungry.

Are you kidding me? She made me stop at McDonalds three times on the way over here. She's an undercover fatass.

by I'm at a loss for names. June 23, 2010