Sludge

The sludge was a dark brown color and had a strong odor.

The students felt a sludge of boredom during the uninteresting lecture.

The swamp was filled with sludge, making it difficult to navigate.

The treatment plant generates sludge that must be disposed of properly.

The thick sludge of mud made it difficult to walk in the field.

The bottom of the lake was covered in sludge and debris.

The sludge was thick and difficult to handle, so the workers had to wear protective gear.