Which term describes something performed with superficial ease or insincerity?

The term that accurately reflects something performed with superficial ease or insincerity is "glib." This word is often used to describe speech or behavior that appears to be smooth and effortless on the surface, yet lacks depth or genuine thoughtfulness. When someone is glib, they may communicate in a manner that sounds confident and persuasive, but their words often lack sincerity or authenticity, which can lead to mistrust or skepticism from others.

In contrast, "fluent" typically refers to a smooth and articulate expression, particularly in language, without any implication of insincerity. "Effortless" suggests that a task is performed with ease and natural skill, again without any connotation of superficiality or dishonesty. Similarly, "natural" refers to something that is unforced and genuine, lacking any pretense or artifice. Therefore, "glib" stands out as the most fitting term for actions or speech that are characterized by superficial ease combined with insincerity.