sul ‧ ly /ˈsʌli/ BrE AmE verb ( past tense and past participle sullied , present participle sullying , third person singular sullies ) [transitive] formal or literary
[ Date: 1500-1600 ; Origin: Probably from Old French soiller ; ⇨ ↑ soil 2 ]
to spoil or reduce the value of something that was perfect:
a scandal that sullied his reputation