supernumerary vs excess

supernumerary and excess both are nouns.

Word	Noun	Adjective	Verb	Adverb
supernumerary	Yes	Yes	No	No
excess	Yes	Yes	No	No

As adjectives, supernumerary and excess are synonyms defined as:

Other synonyms of supernumerary include extra, redundant, spare, supererogatory, superfluous, surplus.

supernumerary (noun)	excess (noun)
a minor actor in crowd scenes	excessive indulgence
a person serving no apparent function	immoderation as a consequence of going beyond sufficient or permitted limits
	a quantity much larger than is needed
	the state of being more than full

supernumerary (adjective)	excess (adjective)
more than is needed, desired, or required	more than is needed, desired, or required