When something hits you out of left field and you can't help but cry. An unexpected solemn event that tends to swell up sad feelings.
Something about the way she said "goodbye" made me come undone.
by daniel April 20, 2005
To come right before you girlfriend, preventing her from coming.
I come undone to her yesterday, and she was so mad at me!
by Loststylus November 10, 2010