|Origin:||ternir 'to make dull'|
if an event or fact tarnishes someone's reputation, record, image etc, it makes it worse:
His regime was tarnished by human rights abuses.
2 [intransitive and transitive]
if metals such as silver, copper, or brass tarnish, or if something tarnishes them, they become dull and lose their colour:
Gold does not tarnish easily.
tarnished silver spoons