thunderstruck vs flabbergasted

thunderstruck and flabbergasted both are adjectives.

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

As adjectives, thunderstruck and flabbergasted are synonyms defined as:

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

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

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