Hypothec refers to the action of pledging a property as security for a loan. Synonyms for this word include mortgage, lien, security, and pledge. These terms are often used in legal and financial contexts. A mortgage is a loan specifically for purchasing a property, where the property itself acts as collateral. A lien is a legal claim on a property to ensure payment of a debt. Security refers to any asset pledged as collateral, while pledge is a formal promise to pay back a debt. As with many legal and financial terms, it's important to use these synonyms correctly to avoid confusion and ensure professional communication.