professing vs affirmation

professing and affirmation both are nouns.

Word	Noun	Adjective	Verb	Adverb
professing	Yes	No	No	No
affirmation	Yes	No	No	No

As nouns, affirmation is a hypernym of professing; that is, affirmation is a word with a broader meaning than professing:

Other hypernyms of professing include avouchment, avowal.

professing (noun)	affirmation (noun)
an open avowal (true or false) of some belief or opinion	a judgment by a higher court that the judgment of a lower court was correct and should stand
	a statement asserting the existence or the truth of something
	(religion) a solemn declaration that serves the same purpose as an oath (if an oath is objectionable to the person on religious or ethical grounds)
	the act of affirming or asserting or stating something