rapacity vs mortal sin

rapacity and mortal sin both are nouns.

Word	Noun	Adjective	Verb	Adverb
rapacity	Yes	No	No	No
mortal sin	Yes	No	No	No

As nouns, mortal sin is a hypernym of rapacity; that is, mortal sin is a word with a broader meaning than rapacity:

rapacity: reprehensible acquisitiveness; insatiable desire for wealth (personified as one of the deadly sins)
mortal sin: an unpardonable sin entailing a total loss of grace

Other hypernyms of rapacity include deadly sin.

rapacity (noun)	mortal sin (noun)
reprehensible acquisitiveness; insatiable desire for wealth (personified as one of the deadly sins)	an unpardonable sin entailing a total loss of grace
extreme gluttony
(of an animal, usually a bird) The quality of subsisting off live prey.