Which word refers to something that is transparently thin?

The term that refers to something that is transparently thin is "diaphanous." This word is often used to describe delicate fabrics or materials that allow light to pass through them, creating an ethereal or sheer appearance. For example, a diaphanous gown might be made of a lightweight, translucent fabric that enhances the gracefulness of the wearer while still being suggestive rather than fully revealing.

The other words in the choices do not possess this meaning. "Dilatory" refers to a tendency to delay or procrastinate, "desuetude" indicates a state of disuse or inactivity, and "edifying" describes something that enlightens or instructs, often in a moral or intellectual way. Each of these terms relates to different concepts, making "diaphanous" the clear choice for describing something that is transparently thin.