To be completely devastated. It comes from the highest scoring action in the sport of cricket:- where the ball exits the circle without leaving the ground.
I was knocked for six after my husband left me


My car was knocked for six after I rammed it into a wall.
by Kung-Fu Jesus April 28, 2004
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Very very drunk. also see Pissed Blitzed
The boss to a waiter: Dont put that much liquor in their drink or their be knocked for six!
by Howard Owen June 17, 2007
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