Underletting is a term used in real estate that refers to the practice of letting a property at a rent that is lower than the market rate. It's often seen as a way for landlords to fill a vacant property quickly, but it can also be seen as giving away financial potential. Other synonyms for underletting might include subleasing, subletting, or renting below market value. These terms all refer to the same general concept of allowing someone to use a property, often for less than it might be worth. In many cases, underletting or subletting can be a great way to earn extra income or fill a vacant space, but it's important to consider the potential risks and benefits before making any decisions.