passerby vs footer

passerby and footer both are nouns.

Word	Noun	Adjective	Verb	Adverb
passerby	Yes	No	No	No
footer	Yes	No	No	No

As nouns, footer is a hypernym of passerby; that is, footer is a word with a broader meaning than passerby:

Other hypernyms of passerby include pedestrian, walker.

passerby (noun)	footer (noun)
a person who passes by casually or by chance	a printed note placed below the text on a printed page
	a person who travels by foot
	(used only in combinations) the height or length of something in feet