1. 
[syn: shock, floor, ball over, blow out of the water, take aback]
WordNet (r) 3.0 (2006):
take aback
    v 1: surprise greatly; knock someone's socks off; "I was floored
         when I heard that I was promoted" [syn: shock, floor,
         ball over, blow out of the water, take aback]
Moby Thesaurus II by Grady Ward, 1.0:
19 Moby Thesaurus words for "take aback":
   abash, appall, astound, bowl down, bowl over, confound, discomfit,
   disconcert, dismay, electrify, frighten, jar, jolt, put out, shake,
   shock, stagger, startle, stun