The word "besoils" refers to the action of covering or staining something with oil, dirt or other substances. Some synonyms for this word include:
1. Stain: This refers to a discoloration that occurs when something is soiled or discolored.
2. Smear: This refers to spreading a substance (like oil or grease) over a surface.
3. Sully: This refers to sullying or dirtying something.
4. Taint: This refers to a kind of contamination or corruption of something.
5. Besmirch: This refers to dishonoring or smearing someone's reputation or name.
Overall, these synonyms capture different aspects of the concept of "besoiling" and can be used interchangeably depending on the context and intended meaning.