regret vs sorrow

regret and sorrow both are nouns.

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

As nouns, regret and sorrow are synonyms defined as:

regret and sorrow: sadness associated with some wrong done or some disappointment

Other synonyms of regret include rue, ruefulness.

regret (noun)	sorrow (noun)
sadness associated with some wrong done or some disappointment	something that causes great unhappiness
	an emotion of great sadness associated with loss or bereavement
	sadness associated with some wrong done or some disappointment
	the state of being sad

regret (verb)	sorrow (verb)
decline formally or politely	feel grief
express with regret
feel remorse for; feel sorry for; be contrite about
feel sad about the loss or absence of