contagiousness vs harmfulness

contagiousness and harmfulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
contagiousness	Yes	No	No	No
harmfulness	Yes	No	No	No

As nouns, harmfulness is a hypernym of contagiousness; that is, harmfulness is a word with a broader meaning than contagiousness:

contagiousness: The state or condition of being contagious, easily transmitted to others.
harmfulness: the quality of being noxious

Other hypernyms of contagiousness include noisomeness, noxiousness.

contagiousness (noun)	harmfulness (noun)
The state or condition of being contagious, easily transmitted to others.	destructiveness that causes harm or injury
	the quality of being noxious