dumbfounded vs flabbergasted

dumbfounded and flabbergasted both are adjectives.

Word	Noun	Adjective	Verb	Adverb
dumbfounded	No	Yes	No	No
flabbergasted	No	Yes	No	No

As adjectives, dumbfounded and flabbergasted are synonyms defined as:

dumbfounded and flabbergasted: as if struck dumb with astonishment and surprise

Other synonyms of dumbfounded include dumbstricken, dumbstruck, dumfounded, stupefied, thunderstruck.

dumbfounded (adjective)	flabbergasted (adjective)
as if struck dumb with astonishment and surprise	as if struck dumb with astonishment and surprise