Unbirthdayish

When you say something, or behave badly. On someone's birthday.
It's very "Unbirthdayish"

Dude, you didn't need to say that to Nicki on her birthday, that's really "unbirthdayish"

by Miss Nilla December 19, 2016

Unbirthday

Any day that isn't technically your date of birth.
Refers to Louis Carroll's Alice in Wonderland, where there Mad Hatter and his crew celebrate such a day.
Can also be utilized for no damn reason except to celebrate..

Today is my Unbirthday, three and one.

by REBel Siren January 2, 2023