covetousness vs mortal sin

covetousness and mortal sin both are nouns.

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

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

covetousness: 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 covetousness include deadly sin.

covetousness (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 greed for material wealth
an envious eagerness to possess something