<p><strong>Adjective</strong></p><ul><li>not sharp</li><li>blunt</li><li>causing boredom</li><li>tedious</li><li>uninteresting</li><li>not lively or spirited</li><li>listless</li><li>not bright, intense, or clear</li><li>dim</li><li>having very little depth of color</li><li>lacking in richness or intensity of color</li><li>slow in motion or action</li><li>not brisk</li><li>sluggish</li><li>mentally slow</li><li>lacking brightness of mind</li><li>somewhat stupid</li><li>obtuse</li><li>lacking keenness of perception in the senses or feelings</li><li>insensible</li><li>unfeeling</li><li>not intense or acute</li></ul><p><strong>Synonyms</strong></p><ul><li>vapid</li><li>dreary</li><li>tiresome</li><li>boring</li><li>inert</li><li>inactive</li><li>torpid</li><li>apathetic</li><li>unimaginative</li><li>stolid</li><li>unintelligent</li><li>benumb</li><li>deaden</li><li>blunt</li><li>discourage</li><li>dishearten</li><li>depress</li></ul><p><strong>Antonyms</strong></p><ul><li>keen</li><li>sharp</li><li>interesting</li><li>bright</li></ul><p><strong>Comparative</strong></p><ul><li>duller</li></ul><p><strong>Superlative</strong></p><ul><li>dullest</li></ul>