<p><strong>Verb</strong></p><ul><li>(used with object) to make black; darken.</li><li>to speak evil of; defame: to blacken a person's reputation.</li></ul><p><strong>Synonyms</strong></p><ul><li>calumniate</li><li>traduce</li><li>libel</li><li>slander</li><li>smear</li><li>denigrate</li></ul><p><strong>Verb</strong></p><ul><li>(used without object) to grow or become black.</li></ul>