Hands down

In the sentence "Google is the best search engine, hands down", what's the meaning of "hands down"?

"without question," "indisputably"

It comes from Poker I guess. When every one put their cards or "Hands" Down. So when you say it is the best, you're letting people know its not a bluff. Something like that.

possible origin - from genteel world of horseracing:

http://www.word-detective.com/011502.html#handsdown