The word "dirtest" refers to something that is extremely unclean or filthy. There are several synonyms that can be used to describe something that is dirty, including grimy, soiled, filthy, muddy, and sullied. Grimy refers to something covered in dirt or grime, while soiled describes something that has been stained or marked with a substance. Filthy suggests extreme dirtiness or contamination, while muddy signifies dirt mixed with water or moisture. Lastly, sullied refers to something that has been marred or tarnished in some way, making it no longer clean or pure. These synonyms for "dirtest" help provide more descriptive ways to communicate about unclean things.