Someone who is wan is visibly unwell and lacking in energy. If you’ve had the flu for over a week, and you finally get out of bed looking pale and tired, your mother might say that you look wan.
When your aunt comes to dinner and eats three helpings of dessert, she might seem a little wan as she drinks her tea, meaning she looks sickly and weak — and no wonder, after so many slices of pie! Wan can also describe a fading light — one that is sickly and weak, just like your aunt. When the light bulb in the living room burns out and leaves only wan twilight filtering in, you’ll find it impossible to read.