flabbergast

“flabbergasted”:
agape, aghast, agog, all agog, amazed, astonished, astounded,
at gaze, awed, awestruck, beguiled, bewildered, bewitched,
breathless, captivated, confounded, dumbfounded, dumbstruck,
enchanted, enraptured, enravished, enthralled, entranced,
fascinated, gaping, gauping, gazing, hypnotized, in awe, in awe of,
lost in wonder, marveling, mesmerized, open-eyed, openmouthed,
overwhelmed, popeyed, puzzled, rapt in wonder, spellbound,
staggered, staring, stupefied, surprised, thunderstruck,
under a charm, wide-eyed, wonder-struck, wondering