not put it past someone
not put (something) past (one)
1. To believe one is capable of doing something unsavory, immoral, illicit, selfish, etc. He's a very charming guy, but I wouldn't put it past him to stab me in the back if it meant advancing his career.
2. To be unable to swindle, fool, or deceive one. MY grandmother might be 85, but you still can't put a thing past her! That sleazy used car salesman couldn't put his bogus little scam past me.
not put it past (someone)
To not dismiss or rule out the possibility that someone has engaged in a particular kind of bad behavior, based on that person's previous pattern of behavior. Do I think Joe stole the money? Honestly, I wouldn't put it past him. He has no conscience. It seems a bit far-fetched that the government is spying on us with our own appliances, but I wouldn't put it past them.