superbly vs marvellously

superbly and marvellously both are adverbs.

Word	Noun	Adjective	Verb	Adverb
superbly	No	No	No	Yes
marvellously	No	No	No	Yes

As adverbs, superbly and marvellously are synonyms defined as:

Other synonyms of superbly include marvelously, terrifically, toppingly, wonderfully, wondrous, wondrously.

superbly (adverb)	marvellously (adverb)
(used as an intensifier) excellently	(used as an intensifier) excellently