Her reputation remained stainless as she upheld impeccable moral standards.

stainless 是由名词 stain（污点、瑕疵）加上否定后缀 -less（表示"没有"）构成的形容词，字面意思是"没有污点的"，引申为"纯洁无瑕的"或"无可指摘的"。