greed vs mortal sin

greed and mortal sin both are nouns.

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

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

greed: 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 greed include deadly sin.

greed (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
excessive desire to acquire or possess more (especially more material wealth) than one needs or deserves