Any day that is not your birthday, signifying that each day we are closer to death.
"Happy Deathday to you,
One day closer to
The day that you die,
and your life is through!"
n. 1. The day you Permanently Failed at life.
2. A planned day of departure from this world
3. When "Hey Guys, WATCH THIS!", didnt end so well
1. Looks like John celebrated his Deathday today.
2. Emo: I am having my Deathday tomorrow if anyone wants to come... not that anyone cares ~boohoo~
3. Jerry: HEY GUYS, WATCH THIS!"
~proceeds to fall and snap neck~
Jerry's so-called friend: Happy Deathday Jerry!