Guile
Etymology
From Old French guile, "deceit, cunning," most likely of Germanic origin and related to the same root as "wile." Unusually for this batch, it is not from Latin. The word has kept its medieval flavor of the sly stratagem — the ruse laid by someone too clever, and too indirect, to attack head-on.
noun · /GYLE/
Sly cunning — cleverness used to deceive or manipulate, often behind a disarming manner.
What it names
The trait of the crafty operator who gets their way by artful trickery rather than force or open dealing.
Example
With practiced guile, the negotiator let the other side believe the concession had been their own idea.
Related idea
Duplicity is the two-faced maintenance of a false front; guile is more about ingenuity — the crafty ruse or stratagem itself, sometimes almost admired.