Which word signifies cunning treachery or skillful deceit?

The term that signifies cunning treachery or skillful deceit is "guile." This word is often associated with the ability to manipulate or deceive others through cleverness or insincerity. It implies a level of cunning that goes beyond simple trickery; guile suggests a deeper level of strategy and craftiness in achieving one's aims, often at the expense of others or with a sense of deceit.

The word "gush" typically refers to an expression of enthusiasm or excessive praise, which does not relate to deceit. "Hack" generally refers to a crude or inept effort, often in terms of work or creativity, rather than manipulation or deceit. "Heinous" describes acts that are shockingly evil or wicked, but it does not specifically pertain to cunning or deceitful behavior. Thus, "guile" is the most appropriate choice that encompasses the essence of cunning treachery and skillful deceit.