fallout vs consequence

fallout and consequence both are nouns.

Word	Noun	Adjective	Verb	Adverb
fallout	Yes	No	No	No
consequence	Yes	No	No	No

As nouns, consequence is a hypernym of fallout; that is, consequence is a word with a broader meaning than fallout:

fallout: any adverse and unwanted secondary effect
consequence: a phenomenon that follows and is caused by some previous phenomenon

Other hypernyms of fallout include effect, event, issue, outcome, result, upshot.

fallout (noun)	consequence (noun)
any adverse and unwanted secondary effect	having important effects or influence
the radioactive particles that settle to the ground after a nuclear explosion	the outcome of an event especially as relative to an individual
	a phenomenon that follows and is caused by some previous phenomenon