death vs deathly

death is a noun but deathly is not a noun.

Word	Noun	Adjective	Verb	Adverb
death	Yes	No	No	No
deathly	No	Yes	No	Yes

death (noun)	deathly (noun)
the act of killing
the event of dying or departure from life
the permanent end of all life functions in an organism or part of an organism
the absence of life or state of being dead
a final state
the time when something ends
the time at which life ends; continuing until dead

death (adjective)	deathly (adjective)
	having the physical appearance of death
	causing or capable of causing death

death (adverb)	deathly (adverb)
	to a degree resembling death
	to an extreme degree