shadowy
Dim, dark, and hard to see clearly.
Shadowy describes something dim, dark, and hard to see clearly, like a figure moving in the shadows at dusk. When detectives in a mystery novel follow a shadowy figure down an alley, they can barely make out the person's shape. A shadowy corner of a basement is the kind of spot where spiders build webs undisturbed.
The word also describes things that are mysterious, secretive, or not fully known. A shadowy organization operates in secret, keeping its activities hidden from public view. When historians piece together information about shadowy figures from the past, they're working with incomplete records and uncertain facts, like trying to see something in poor light.
Notice how the two meanings connect: just as shadows make things physically hard to see, secrecy makes information hard to know. A shadowy character in a spy novel might literally lurk in shadows, but they're also mysterious, with unclear motives and a hidden past. When something is shadowy, whether it's a darkened hallway or a suspicious business deal, you're left squinting and uncertain, unable to see the full picture clearly.