Diaphanous

SHEER

This fabric is so thin and delicate that light easily passes through it.

The word "diaphanous" means something that's very light, delicate, and almost see-through, which is exactly what "sheer" describes. Both words are often used to talk about thin, translucent fabrics like chiffon or gauze. Since "sheer" fits the definition perfectly and matches the number of letters, it’s the correct answer. No wordplay here—just a straightforward synonym.