fadeout vs disappearance

fadeout and disappearance both are nouns.

Word	Noun	Adjective	Verb	Adverb
fadeout	Yes	No	No	No
disappearance	Yes	No	No	No

As nouns, disappearance is a hypernym of fadeout; that is, disappearance is a word with a broader meaning than fadeout:

fadeout (noun)	disappearance (noun)
a slow or gradual disappearance	the act of leaving secretly or without explanation
a gradual temporary loss of a transmitted signal due to electrical disturbances	gradually ceasing to be visible
	the event of passing out of sight
	ceasing to exist