<p><strong>Noun</strong></p><ul><li>A person who vouches or is responsible for a person or thing.</li><li>Synonyms: guarantor, backer, patron.</li><li>A person, firm, organization, etc., that finances and buys the time to broadcast a radio or television program so as to advertise a product, a political party, etc.</li><li>Synonyms: advertiser.</li><li>A person who makes a pledge or promise on behalf of another.</li><li>Christianity: a person who promises to mentor a youth or new convert preparing for confirmation or initiation, or who answers for an infant at baptism.</li></ul><p><strong>Verb</strong></p><ul><li>To act as sponsor for; promise, vouch, or answer for.</li><li>Synonyms: underwrite, back, finance, guarantee.</li></ul>