Merriam-Webster Online Dictionary
astonish (verb)transitive verb
1.
obsolete to strike with sudden fear
2.
to strike with sudden and usually great wonder or surprise - was too astonished to speak surprise
Merriam-Webster Online Thesaurus
astonish (verb)to make a strong impression on (someone) with something unexpected
SYNONIMS:
amaze, astonish, astound, bowl over, dumbfound ( dumfound), flabbergast, floor, rock, shock, startle, stun, stupefy, thunderstrikeRELATED WORDS:
befuddle, bewilder, blindside, blow away, confound, confuse, daze, discomfit, disconcert, dismay, jar, muddle, nonplus, perplex, shake up