Unstable Character Design 

When a specific character from an animated series or TV show can have obvious but not permanent changes to their look such as: hair style or color, clothing, glasses or other accessories.

Princess Bubblegum from Adventure Time has an Unstable character design.

Unstable Character Design by Maxamagican June 6, 2020

emotionally unstable

Intense mood swing;
A minor event may trigger an extreme emotional outburst.

Emotionally unstable; Jake didn't invite me to the party... He hates me and so does everyone else.

emotionally unstable by café February 17, 2015

Unstable_Day 

1. A popular Operative in The Days Union 2. Clearly has rabies 3. S h o r t . 4. He is the cyan Operative. 5. A dysfunctional-twitchy existence.

Person 1: Unstable_Day is so cool!
Person 2: He's literally a-
Person 1: UNSTABLE_DAY IS SO COOL.

Unstable_Day by Days Union <3 December 6, 2021

undatable

not able to be dated at all

the writer of this definition is undatable

undatable by c1094 September 11, 2013

unstable cheese 

Cheese that comes from the Fast Food stores where the cheese on the burgers is not cooked right and if breaks off while you hold it in your hands. Often you find yourself in the situation where you are using your laptop, or playing a PSP. or simply reading the newspaper. then a piece of cheese breaks off and lands on whatever gets on it's way.

Person #1: O'sht, unstable cheese got my PSP screen!
Person #2: Har Har, should sue Macdonald's for it. If fat people can sue them for being fat, then it wount hurt if we sue for Unstable cheese.

unstable cheese by SmexMuffinMan December 7, 2006

unstable 

microsoft windows

unstable by Anonymous September 19, 2003

Unrailable  

When a bitch is so nasty that even if you're completly drunk you wouldn't rail her.

"Omg Cindy is such a slut, I'm wasted but still she's Unrailable ."

Unrailable by E-glue July 27, 2008