affirmative vs favourable

affirmative is a noun but favourable is not a noun.

Word	Noun	Adjective	Verb	Adverb
affirmative	Yes	Yes	No	No
favourable	No	Yes	No	No

affirmative (noun)	favourable (noun)
a reply of affirmation

affirmative (adjective)	favourable (adjective)
affirming or giving assent	(of winds or weather) tending to promote or facilitate
expressing or manifesting praise or approval	encouraging or approving or pleasing
expecting the best	giving an advantage
	presaging or likely to bring good luck or a good outcome