Renunciation on oath; forswearing, esp. of heretical opinions; (also) an instance of this. Now chiefly historical.

Avowal, declaration, or affirmation of allegiance; an instance of this.

a vow to renounce speech, esp. taken by members of certain religious or monastic orders (cf. sense A. 1b); (in extended use) a promise or commitment…

a solemn promise of loyalty, support, and obedience, originally made to a temporal or spiritual leader (esp. the reigning monarch or pope), but now…

A solemn promise of fidelity or faithful attachment. Also const. of (faith, love, etc.).

Sworn confirmation of a fact, promise, or obligation; esp. sworn confirmation of one's intent to marry. Also: an instance of this.

Official repudiation on oath of a religious, political, or other principle; rejection or disavowal of a claim or claimant. Also: an instance of this.

In representations of African languages: incantation, worship; a magical or religious rite or observance; an oath. Obsolete.

= affidation, n.

a solemn oath of loyalty, esp. to a nation; spec. (frequently with capital initials) an oath of allegiance to (the flag of) the United States.

Law. An oath before a justice or coroner undertaking to leave the country for ever, made by a criminal in order to escape punishment, after taking…

the oath taken by a Guide, used as a protestation of honour and sincerity. transferred in jocular use.