I wouldn't put it past (someone) phrase spoken informal
The phrase can be followed by "to do something".
Used to say that if someone did anything, especially something bad, it would not surprise you because it is his/her characteristic.
They rejected my suggestion again, but I wouldn't put it past them. I know they don't like me.
I wouldn't put it past Leon to tell lies. He is unreliable.
Tiffany got a bad mark, but I wouldn't put it past her. She didn't study at all.
This expression uses past in the sense of “beyond” [the Late 1800s]