from The Century Dictionary.
- Unfit to be pleaded or urged as a plea.
Sorry, no etymologies found.
It is a blindness brought upon a man, because he would not see; otherwise all ignorance, that is merely negative and inculpable presumption, is utterly inconsistent with, and makes absolutely unpleadable.
So that if terror set home with evidence, or evidence edged with terror, could convince, ignorance was here unpleadable.