<p><strong>Adjective</strong></p><ul><li>calm, peaceful, or tranquil; unruffled: a serene landscape; serene old age.</li><li>Synonyms: unperturbed, undisturbed, collected, composed, imperturbable</li><li>Antonyms: disturbed</li><li>clear; fair: serene weather.</li><li>Synonyms: unclouded</li><li>Antonyms: clouded</li><li>Usually Serene: most high or august (used as a royal epithet, usually preceded by his, your, etc.): His Serene Highness.</li></ul><p><strong>Noun</strong></p><ul><li>serenity; tranquility: the serene of early morning at the lake.</li><li>Archaic: a clear or tranquil expanse of sea or sky.</li></ul>