<p><strong>Adjective</strong></p><ul><li>serious and zealous in intention, purpose, or effort: an earnest worker.</li><li>Synonyms: ambitious, industrious, determined, purposeful, intent, fervent</li><li>Antonyms: frivolous</li><li>showing depth and sincerity of feeling: earnest words; an earnest entreaty.</li><li>seriously important; demanding or receiving serious attention.</li></ul><p><strong>Noun</strong></p><ul><li>seriousness and zealousness: to speak in earnest.</li></ul>