sorrow vs poignancy

sorrow and poignancy both are nouns.

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

As nouns, poignancy is a hyponym of sorrow; that is, poignancy is a word with a more specific, narrower meaning than sorrow:

Other hyponyms of sorrow include bereavement, mourning, poignance.

sorrow (noun)	poignancy (noun)
something that causes great unhappiness	a quality that arouses emotions (especially pity or sorrow)
an emotion of great sadness associated with loss or bereavement	a state of deeply felt distress or sorrow
sadness associated with some wrong done or some disappointment
the state of being sad

sorrow (verb)	poignancy (verb)
feel grief