unbirthday
(redirected from unbirthdays)unbirthday
(ˌʌnˈbɜːθdeɪ)n
jocular
a. any day other than one's birthday
b. (as modifier): an unbirthday present.
[C19: coined by Lewis Carroll in Through the Looking-Glass]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014