Unbirthday

//ʌnˈbɜːθ.deɪ// noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A day that is not one's birthday but is celebrated as though it were.

    ""They gave it me," Humpty Dumpty continued thoughtfully, as he crossed one knee over the other and clasped his hands round it, "they gave it me⸺for an un-birthday present." / "I beg your pardon?" Alice said with a puzzled air." / "I'm not offended," said Humpty Dumpty. / "I mean, what is an un-birthday present?" / "A present given when it isn't your birthday, of course.""

Example

More examples

""They gave it me," Humpty Dumpty continued thoughtfully, as he crossed one knee over the other and clasped his hands round it, "they gave it me⸺for an un-birthday present." / "I beg your pardon?" Alice said with a puzzled air." / "I'm not offended," said Humpty Dumpty. / "I mean, what is an un-birthday present?" / "A present given when it isn't your birthday, of course.""

Etymology

From un- + birthday, coined by English writer Lewis Carroll (1832–1898) in Through the Looking-Glass (1871).

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.