deadness vs lifelessness

deadness and lifelessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
deadness	Yes	No	No	No
lifelessness	Yes	No	No	No

As nouns, lifelessness is a hypernym of deadness; that is, lifelessness is a word with a broader meaning than deadness:

Other hypernyms of deadness include inanimateness.

deadness (noun)	lifelessness (noun)
the inanimate property of something that has died	not having life
the physical property of something that has lost its elasticity	a state of no motion or movement
the quality of being unresponsive; not reacting; as a quality of people, it is marked by a failure to respond quickly or with emotion to people or events