To believe that someone is incapable or unwilling to engage in some sort of extreme behavior or action. Usually used in negative constructions. A: "Do you think Joe stole the money?" B: "Honestly, I wouldn't put it past him. He has no conscience."You're more naïve than I thought if you would put unauthorized spying on private citizens past the government.
put past
v.
To believe some action, especially an extreme action, to be of a kind that someone would not do. Often used negatively: I wouldn't put it past those kids to try to climb to the top of the flagpole. Would you put murder past these thugs?