blow someone away —(sl.)
1. affect smb. with overwhelming enthusiasm:
- The whole idea just blew her away.
2. (Underworld) kill a person:
- The boss said we was to blow you away if you gives us any trouble.
blow someone off—(sl.)
1. neglect or ignore a person:
- Don’t blow me off. Listen! I want it done now.
2. cheat or deceive a person:
- They blew off a young couple and conned a hundred bucks out of them.
Note: Neither expression correlates in meaning with the phrase blow someone out of the water—(sl.)
1. utterly surprise a person:
- To say the film exceeded my expectations is an understatement; it completely blew me out of the water.
2. defeat a competitor decisively:
- They also believe that if they fall behind in the functionality race, the competition will blow them out of the water.