A blagger is the person who does the blagging: someone who gets what they want with a clever story, a straight face, and a lot of talk. In the sense you will meet most, this is not a violent thief. It is the friend who always talks the door person round, the one who somehow never pays for the taxi. The meaning you are writing about stresses lying, and that is fair, because a blag often uses a false or half-true tale. Though actually, in loose British speech it can sound almost admiring — “he’s a bit of a blagger” can mean cheeky and good at it, not only bad. Still informal, still British. Do not use it for a lawyer or a teacher who persuades people in an official way; that is a different kind of talk.

靠說話唬人、把東西弄到手的人（英式口語）。