Surprise greatly; knock someone's socks off.

synonyms: ball over, blow out of the water, floor, shock.

Roget 508: not expect etc. 507; be taken by surprise; start; miscalculate etc. 481; not bargain for; come upon, fall upon.    be unexpected etc. adj.; come unawares etc. adv.; turn up, pop, drop from the clouds; come upon one, burst upon one, flash upon one, bounce upon one, steal upon one, creep upon one; come like a thunder clap, burst like a thunderclap, thunder bolt; take by surprise, catch by surprise, catch unawares, catch napping; yach [S. Afr.].    pounce upon, spring a mine upon.    surprise, startle, take aback, electrify, stun, stagger, take away one's breath, throw off one's guard; astonish, dumbfound etc. (strike with wonder) 870.    ... show more