tarnishes

/ˈtɑːr.nɪʃ/

动词

（使）（尤指金属）失去光泽，（使）变暗淡；（使）褪色
诽谤；中伤
By this time a series of scandals had severely tarnished the candidate's image/reputation.
到这时，一连串的丑闻已使这名候选人的形象／名誉大大受损。