sin vs deadly sin

sin and deadly sin both are nouns.

Word	Noun	Adjective	Verb	Adverb
sin	Yes	No	Yes	No
deadly sin	Yes	No	No	No

As nouns, deadly sin is a hyponym of sin; that is, deadly sin is a word with a more specific, narrower meaning than sin:

sin: an act that is regarded by theologians as a transgression of God's will
deadly sin: an unpardonable sin entailing a total loss of grace

Other hyponyms of sin include fall, actual sin, original sin, mortal sin, venial sin.

sin (noun)	deadly sin (noun)
an act that is regarded by theologians as a transgression of God's will	an unpardonable sin entailing a total loss of grace
estrangement from god
the 21st letter of the Hebrew alphabet
ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle

sin (verb)	deadly sin (verb)
commit a sin; violate a law of God or a moral law
commit a faux pas or a fault or make a serious mistake