<p><strong>Verb (used with object)</strong></p><ul><li>To take upon oneself, as a task, performance, etc.; attempt: She undertook the job of answering all the mail.</li><li>To promise, agree, or obligate oneself (followed by an infinitive): The married couple undertook to love, honor, and cherish each other.</li><li>To warrant or guarantee (followed by a clause): The sponsors undertake that their candidate meets all the requirements.</li><li>To take in charge; assume the duty of attending to: The lawyer undertook a new case.</li></ul><p><strong>Verb (used without object)</strong></p><ul><li>Archaic: to engage oneself by promise; give a guarantee, or become surety.</li></ul>