excessively vs to a fault

excessively and to a fault both are adverbs.

Word	Noun	Adjective	Verb	Adverb
excessively	No	No	No	Yes
to a fault	No	No	No	Yes

As adverbs, excessively and to a fault are synonyms defined as:

excessively and to a fault: to a degree exceeding normal or proper limits

Other synonyms of excessively include overly, too.

excessively (adverb)	to a fault (adverb)
to a degree exceeding normal or proper limits	to a degree exceeding normal or proper limits