expiation vs redemption

expiation and redemption both are nouns.

Word	Noun	Adjective	Verb	Adverb
expiation	Yes	No	No	No
redemption	Yes	No	No	No

As nouns, redemption is a hypernym of expiation; that is, redemption is a word with a broader meaning than expiation:

expiation: the act of atoning for sin or wrongdoing (especially appeasing a deity)
redemption: (theology) the act of delivering from sin or saving from evil

Other hypernyms of expiation include salvation.

expiation (noun)	redemption (noun)
the act of atoning for sin or wrongdoing (especially appeasing a deity)	the act of purchasing back something previously sold
compensation for a wrong	(theology) the act of delivering from sin or saving from evil
	repayment of the principal amount of a debt or security at or before maturity (as when a corporation repurchases its own stock)