I would recast that definition ... as "one who boasts of his ability to deceive (con)."

Hey, tsuwm. I can't imagine why anyone would want to boast he is a cunning liar.
Who would believe him? :)

More likely his 'falsehoods' are a ruse for the unwary.

Remember Shakespeare's Prince Hal:

So, when this loose behavior I throw off
And pay the debt I never promised,
By how much better than my word I am,
By so much shall I falsify men's hopes;
And like bright metal on a sullen ground,
My reformation, glittering o'er my fault,
Shall show more goodly and attract more eyes
Than that which hath no foil to set it off.
I'll so offend, to make offence a skill;
Redeeming time when men think least I will.
Henry IV, Part 1, Act I, Scene II