frightfully vs awful

frightfully is not an adjective while awful is an adjective.

Word	Noun	Adjective	Verb	Adverb
frightfully	No	No	No	Yes
awful	No	Yes	No	Yes

As adverbs, frightfully and awful are synonyms defined as:

Other synonyms of frightfully include awfully, terribly.

frightfully (adjective)	awful (adjective)
	offensive or even (of persons) malicious
	causing fear or dread or terror
	exceptionally bad or displeasing
	extreme in degree or extent or amount or impact
	inspiring awe or admiration or wonder
	inspired by a feeling of fearful wonderment or reverence

frightfully (adverb)	awful (adverb)
used as intensifiers	used as intensifiers