a crook
Examples
There's one way to find out if a man is honest - ask him. If he says "yes" you know he is a crook.
Just when you think there's nothing to write about, Nixon says, "I am not a crook." Jimmy Carter says, "I have lusted after women in my heart." President Reagan says, "I have just taken a urinalysis test, and I am not on dope."
I know many crooks and they never preach, but I don't know anyone who preaches that isn't a crook also.
I am a politician which means I am a liar and a crook. When I am not kissing babies I am stealing their lollypops.
For a long time I've been telling Stalin that Beria is a crook but Stalin won't listen.
I know me, and those close to me know me. But sadly, the outside world thinks I'm some kind of a crook.