cocked hat 
/ˈkɑ:kt-/ noun
plural ∼ hats /ˈkɑ:kt-/ noun [count] old-fashioned : a hat with the edges turned up on two or three sides
into a cocked hat
informal 1 US : into a state of confusion, ruin, etc.
▪ The discovery has knocked/thrown all our old assumptions into a cocked hat. [=has completely destroyed all our old assumptions] 2 Brit — used to say that one person or thing is much better than another ▪ The old design was good, but this new one knocks/beats it into a cocked hat.
▪ The discovery has knocked/thrown all our old assumptions into a cocked hat. [=has completely destroyed all our old assumptions]
