the mind > mental capacity > knowledge > conformity with what is known, truth > disregard for truth, falsehood > lack of truth, falsity > an error, mistake > blunder [verb (intransitive)] > embarrassingly (2)
intransitive. To make a false step. Also transitive: to tread (a step) wrongly.
A book in which copies are written or printed for pupils to imitate. to blot one's copybook (colloquial): to commit a fault, misdemeanour or gaffe…