Fifteen Puzzle 

Not to be confused with the vintage board game of the same name, fifteen puzzle is an 1800's phrase referring to total confusion.

“I'm feeling rather fifteen puzzle about this. Are you sure that dogs don't meow?”

Fifteen Puzzle by C L G January 31, 2021

Fifteen Miles of Bad Road

When someone, as they age, goes from looking hot to looking like fifteen miles of bad road

Have you seen Lia? She was hot in high school! She looks like fifteen miles of bad road now.

Fifteen Miles of Bad Road by Siouxsie Supertramp April 27, 2023

fiance fifteen 

the fifteen pounds that many girls lose between their engagement and their wedding.

look at that skinny bitch! she's lost a lot of weight since she got engaged.

well, you know she can't fit in her wedding dress without losing that fiance fifteen. she bought a size 2.

fiance fifteen by wesleywhatwhat July 13, 2010

Facebook Fifteen 

The shortlived fame someone seeks and receives by doing something stupid only for people to forget about it shortly thereafter upon realizing its insignificance.

Joe: dude, did you hear about that girl that drank 20 red bulls a day?
Jeff: yeah, she just wanted her Facebook Fifteen

Facebook Fifteen by Dirk Pitt June 27, 2017

Pen Fifteen 

Pen Fifteen, translated to pen15, then translated from leet, means penis. Used by sofisticated nerd everywhere

User name 'Pen fifteen'
OMG look @ his Pen Fifteen

Pen Fifteen by SensenmanN December 12, 2005

Quarantine Fifteen 

Weight gain acquired during COVID-19 Quarantine Period; fueled by boredom and nervous eating .

I lost my Freshman Fifteen in time for Spring Break but it's coming back as the Quarantine Fifteen.

Quarantine Fifteen by OffLeash2017 March 22, 2020

freshman fifteen 

the phenomenon to put on 15 pounds in your freshman year.

To avoid the Freshman fifteen, you must exercise regularly.

freshman fifteen by Bebel May 23, 2006