marvellously vs superbly

marvellously and superbly both are adverbs.

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

As adverbs, marvellously and superbly are synonyms defined as:

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

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