extra vs excess

extra and excess both are nouns.

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

As adjectives, extra and excess are synonyms defined as:

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

extra (noun)	excess (noun)
something additional of the same kind	excessive indulgence
an additional edition of a newspaper (usually to report a crisis)	immoderation as a consequence of going beyond sufficient or permitted limits
a minor actor in crowd scenes	a quantity much larger than is needed
	the state of being more than full

extra (adjective)	excess (adjective)
further or added	more than is needed, desired, or required
more than is needed, desired, or required
added to a regular schedule

extra (adverb)	excess (adverb)
unusually or exceptionally