1. A situation that is unclear, morally ambiguous, or involves deception and dishonesty
The company's financial dealings are in murky waters.
Os negócios financeiros da empresa estão em águas turvas.
2. Literally, water that is dark, unclear, or difficult to see through
The diver couldn't see much in the murky waters of the lake.
O mergulhador não conseguia ver muito nas águas turvas do lago.