excess vs overindulgence

excess and overindulgence both are nouns.

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

As nouns, excess and overindulgence are synonyms defined as:

excess (noun)	overindulgence (noun)
excessive indulgence	excessive indulgence
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

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