Webster's Revised Unabridged Dictionary · 1913

Disavow

Disavow , transitive verb

[French désavouer; pref. dés- (Latin dis-) + avouer to avow. See Avow, and compare Disavouch.]

1.
To refuse strongly and solemnly to own or acknowledge; to deny responsibility for, approbation of, and the like; to disclaim; to disown; as, he was charged with embezzlement, but he disavows the crime.
A solemn promise made and disavowed. — Dryden
2.
To deny; to show the contrary of; to disprove.
Yet can they never Toss into air the freedom of my birth, Or disavow my blood Plantagenet's. — Ford