society > morality > duty or obligation > moral or legal constraint > immunity or exemption from liability > justification > [noun] > vindication > formal or written (3)
A justifying statement; a spoken, written, or printed defence.
A formal apology for, or defence of, a person, doctrine, course of action, etc.
= apology, n. 1; esp. a written defence or justification of the opinions or conduct of a writer, speaker, etc.