>I can't imagine why anyone would want to boast he is a cunning [conner].

sometimes they just can't help themselves. it's a fairly standard Holywood plot line. Paul Newman as The Hustler boasts about the way he has just hustled some local pool shark and ends up with broken hands as his reward. In David Mamet's House of Games a con artist sets up an elaborate game to con a famous psychologist, and then later boasts about the outcome with his cohorts (which she of course overhears).

so now we have a sesquipedalian word for these characters.