Hypothecation is a term often used in finance and legal arenas to refer to the pledging of assets or collateral to secure a loan. There are several synonyms for this term that can be used to express this concept, including 'mortgage', 'pledge', 'lien', 'security interest', and 'charge'. Each of these terms refers to the act of offering assets as a guarantee of repayment if the borrower defaults on their loan. It is important to understand the nuances of each of these terms, as they may have different legal implications or be used in specific contexts. Nonetheless, each of these words can effectively convey the idea of hypothecation.