superbly vs terrifically

superbly and terrifically both are adverbs.

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

As adverbs, superbly and terrifically are synonyms defined as:

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

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