<p><strong>Adjective</strong></p><ul><li>lacking in consideration for others; inconsiderate; tactless: a thoughtless remark.</li><li>Synonyms: neglectful, negligent</li><li>characterized by or showing lack of thought: think: thought: a shallow, thoughtless book.</li><li>not thinking enough; careless or heedless: thoughtless of his health.</li><li>Synonyms: remiss, inattentive</li><li>devoid of or lacking capacity for thought.</li></ul>