Webster's Revised Unabridged Dictionary · 1913

Affirm

Affirm (af*fẽrm") , transitive verb

[Old English affermen, Old French afermer, French affirmer, affermir, from Latin affirmare; ad + firmare to make firm, firmus firm. See Firm.]

1.
(Law) to assert or confirm, as a judgment, decree, or order, brought before an appellate court for review.
2.
To assert positively; to tell with confidence; to aver; to maintain as true; -- opposed to deny.
Jesus,... whom Paul affirmed to be alive. — Acts xxv. 19
3.
(Law) To declare, as a fact, solemnly, under judicial sanction. See Affirmation, 4.

Affirm , intransitive verb

1.
To declare or assert positively.
Not that I so affirm, though so it seem To thee, who hast thy dwelling here on earth. — Milton
2.
(Law) To make a solemn declaration, before an authorized magistrate or tribunal, under the penalties of perjury; to testify by affirmation.