disculpate
To free from blame or the imputation of a fault; to exonerate.
transitive
He […] endeavoured to disculpate the youth, and left no method untried to soften the tyrant's rage.
Where it comes from
Borrowed from Medieval Latin disculpātus, perfect passive participle of disculpō (“to disculpate”) (see -ate (verb-forming suffix)), from dis- (“off”, denoting the ending of an action) + culpō (“to blame”), from culpa (“fault”) + -ō (verb-forming suffix). Doublet of disculp.
Adapted from the Wiktionary entry disculpate (CC BY-SA 4.0).