Flat Stack

1. Someone who made one thing they enjoy their entire personality

2. Someone with nothing really unique or outstanding about them.
3. This is another form of `basic`.

Did you see that girl over there?

Yeah she is nothing but a flat stack

by Deepandhard December 4, 2022

flat smile

The passive aggressive look you get from your wife when you haven’t done something or, asked for sex. It’s characterised by a straight mouth, with mildly pursed lips, a raised yet furrowed brow, and rarely any verbal communication.

Oh man, she’s given me the flat smile. I’m cooked.

by Poot Rancid November 4, 2023

Flat Spurt

When you cum on a girls chest who is has small breasts

Dave: I so flat spurted on my missus last night!
Jim: Hot yo!

by ChorleyFM July 21, 2010

flat four

A type of an engine configuration; there are four cylinders which are arranged in a flat opposing configuration. They're found in many different Subaru models (The Boxer Engine) and also found in classic VW Beetles.

Everyone panics & hides in their houses when it's snowing out, but not me, my world is flat; I grab my keys & head out to play in my flat four (4 banger)!

by Thorka June 20, 2016

Flat Fart

A fart that is at the same level of noice the whole time

That dog just had a flat fart

by Iggy star September 13, 2017

Flat Milk

When the milk has been left out of the fridge for a prolonged period of time, so the milk is no longer cold and crisp.

"Can you put the milk back in the fridge, it's gone flat"

"Flat Milk is the worst"

by YaMother'sGash August 29, 2016

Flat Fat

When a really obese people loses a ton of weight in a short amount of time, making their appearance seem pinched or unnaturally small

Damn dude, John's wife lost 300 lbs in a week! What a flat fat!

by Ding_Dong_Long_Schlong December 12, 2016