affect vs sadden

affect is a noun but sadden is not a noun.

Word	Noun	Adjective	Verb	Adverb
affect	Yes	No	Yes	No
sadden	No	No	Yes	No

As verbs, sadden is a hyponym of affect; that is, sadden is a word with a more specific, narrower meaning than affect:

affect (noun)	sadden (noun)
the conscious subjective aspect of feeling or emotion

affect (verb)	sadden (verb)
act physically on; have an effect upon	come to feel sad
have an effect upon	make unhappy
make believe with the intent to deceive
have an emotional or cognitive impact upon
connect closely and often incriminatingly