Meaning: Very dirty.

Examples:

Your room is filthy! Time to clean it up!

After I fell down in the mud, my clothes were filthy.

This restaurant has a very filthy bathroom.

Pop Quiz:

Why would we say the dog in the picture is filthy?

A.  Because it has white hair.

B.  Because it has mud all over its body.

C.  Because all dogs are filthy.

To see the correct answer, click on “Continue reading”:

The correct answer is B. Mud is wet dirt, and if you have mud all over you, that means you’re dirty. As you can see in the picture, the dog is very dirty – filthy!