<p><strong>Adjective</strong></p><ul><li>Causing death; deadly; fatal.</li><li>Like death: a deathly silence.</li><li>Of, relating to, or indicating death; morbid: a deathly odor from the sepulcher.</li></ul><p><strong>Adverb</strong></p><ul><li>In the manner of death.</li><li>Very; utterly: deathly afraid.</li></ul>