regret vs refuse

regret and refuse both are nouns.

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

As verbs, refuse is a hypernym of regret; that is, refuse is a word with a broader meaning than regret:

Other hypernyms of regret include decline.

regret (noun)	refuse (noun)
sadness associated with some wrong done or some disappointment	food that is discarded (as from a kitchen)

regret (verb)	refuse (verb)
decline formally or politely	show unwillingness towards
express with regret	not accept as true
feel remorse for; feel sorry for; be contrite about	refuse to let have
feel sad about the loss or absence of	refuse entrance or membership
	elude, especially in a baffling way
	resist immunologically the introduction of some foreign tissue or organ