Glib is fluent. Glib is hip. It is superficial. It is shallow. It is insincere. But it is fluent and hip. The words just roll off the tongue. They can roll off a writer’s manscript as well. The writer is not necessarily insincere as a person, but is writing about a subject in a glib way, because the subject is worthy of it, so the writer thinks. The writer tackles the subject in a insincere way because that is what the writer thinks about the subject. It is unworthy of sincerity.