supersede vs substitute

supersede is not a noun while substitute is a noun.

Word	Noun	Adjective	Verb	Adverb
supersede	No	No	Yes	No
substitute	Yes	Yes	Yes	No

As verbs, substitute is a hyponym of supersede; that is, substitute is a word with a more specific, narrower meaning than supersede:

Other hyponyms of supersede include deputise, deputize, step in, displace, preempt, usurp, oust.

supersede (noun)	substitute (noun)
	a person or thing that takes or can take the place of another
	someone who takes the place of another (as when things get dangerous or difficult)
	an athlete who plays only when a starter on the team is replaced

supersede (adjective)	substitute (adjective)
	artificial and inferior
	serving or used in place of another
	capable of substituting in any of several positions on a team

supersede (verb)	substitute (verb)
take the place or move into the position of	put in the place of another; switch seemingly equivalent items
	be a substitute
	act as a substitute