Crud and Mud

Crud noun - Foul matter that mars the purity or cleanliness of something.

Mud and crud are semantically related in dirt topic. In some cases you can use "Mud" instead a noun "Crud", when it comes to topics like muck.

Mud noun - Water soaked soil; soft wet earth.

Crud and mud are semantically related in dirt topic. You can use "Crud" instead a noun "Mud", if it concerns topics such as muck.