exculpation

nouns

a defense of some offensive behavior or some failure to keep a promise etc.
"he kept finding excuses to stay"; "every day he had a new alibi for not getting a job"; "his transparent self-justification was unacceptable"
alibi, exculpation, excuse, self-justification
the act of freeing from guilt or blame
exculpation
is derived from
exculpate
is a type of (narrower)
the act of excusing a mistake or offense
forgiveness, pardon