poignancy vs sadness

poignancy and sadness both are nouns.

Word	Noun	Adjective	Verb	Adverb
poignancy	Yes	No	No	No
sadness	Yes	No	No	No

As nouns, sadness is a hypernym of poignancy; that is, sadness is a word with a broader meaning than poignancy:

Other hypernyms of poignancy include sorrow, sorrowfulness.

poignancy (noun)	sadness (noun)
a quality that arouses emotions (especially pity or sorrow)	the quality of excessive mournfulness and uncheerfulness
a state of deeply felt distress or sorrow	emotions experienced when not in a state of well-being
	the state of being sad