to spoil something that is pure or someone's perfect reputation玷污;败坏
His reputation, he said, had been unfairly sullied by half-truths and innuendos.他说他的声誉已经被一些半真半假的报道和含沙射影的说法给抹黑了。
to make something dirty弄脏
No speck of dirt had ever sullied his hands.他的双手总是干干净净的。