not put something 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.
See also: not, past, put

not put something past someone

Consider someone capable of doing something, especially something bad. For example, I wouldn't put it past him to tell a lie or two. This expression uses past in the sense of "beyond." [Late 1800s]
See also: not, past, put, someone, something