I was unforgivably careless.
"Lonesome Town"
Ethel and James Dorrance
One must grow old before one can see how unforgivably one was wrong in youth....
"The Black Bag"
Louis Joseph Vance
If any one had spoken to me at that moment, I should have been unforgivably rude.
"The Jervaise Comedy"
J. D. Beresford