terribly vs atrociously

terribly and atrociously both are adverbs.

Word	Noun	Adjective	Verb	Adverb
terribly	No	No	No	Yes
atrociously	No	No	No	Yes

As adverbs, terribly and atrociously are synonyms defined as:

Other synonyms of terribly include abominably, abysmally, awfully, rottenly.

terribly (adverb)	atrociously (adverb)
used as intensifiers	in a terrible manner
in a terrible manner	to an extravagant or immoderate degree