Murk is thick, cloudy darkness that makes it hard to see clearly. Picture a foggy morning when you can barely make out the houses across the street, or muddy water in a pond where you can't see the bottom. That heavy, obscuring gloom is murk.

The word often appears in its adjective form, murky. A murky swimming pool needs cleaning because the water looks dark and uninviting. A murky forest path might feel mysterious or even a little spooky because shadows and mist hide what lies ahead.

People also use murky to describe situations that are confusing or unclear, whether literally dark or figuratively puzzling. When a mystery story has murky details, the clues don't quite add up yet. When someone gives murky instructions, you're left guessing what they really mean. A scandal might involve murky financial dealings, meaning the money trail is deliberately hidden or hard to follow.

The word can carry a sense of something being unclear in a suspicious way. Clear water is trustworthy; murky water makes you wonder what's hiding beneath the surface.