Top Definition
(v) the act of quietly and secretly enjoying a private joke with yourself, to the point of abdominal pain. (that would be why it rhymes with "birthing").
Chris was mirthing to himself in a corner, giving him the acute appearance of an individual in need of a straitjacket.
by the.kanguru March 13, 2011

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×