contagion vs incident

contagion and incident both are nouns.

Word	Noun	Adjective	Verb	Adverb
contagion	Yes	No	No	No
incident	Yes	Yes	No	No

As nouns, incident is a hypernym of contagion; that is, incident is a word with a broader meaning than contagion:

contagion (noun)	incident (noun)
the communication of an attitude or emotional state among a number of people	a single distinct event
an incident in which an infectious disease is transmitted	a public disturbance
any disease easily transmitted by contact

contagion (adjective)	incident (adjective)
	(sometimes followed by `to') minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence
	falling or striking of light rays on something