<p><strong>Verb</strong></p><ul><li>(used with object) To dull the luster of (a metallic surface), especially by oxidation; discolor.</li><li>To diminish or destroy the purity of; stain; sully.</li><li>(used without object) To grow dull or discolored; lose luster; to become sullied.</li></ul><p><strong>Noun</strong></p><ul><li>A tarnished coating.</li><li>Tarnished condition; discoloration; alteration of the luster of a metal.</li><li>A stain or blemish.</li></ul>