The phrase "wash out" generally refers to the process of removing dirt, grime, or unwanted materials from a surface using water. However, there are a number of different synonyms for "wash out" that can provide more specific context or nuance. Some alternative options for "wash out" might include terms like "rinse off," "flush out," "swab down," "scrub away," or "cleanse thoroughly." Depending on the situation or material being cleaned, some of these options may provide a more effective or appropriate solution. Additionally, depending on the context of the phrase "wash out," alternative synonyms might also include terms like "fizzle out," "fail," or "lose strength".