If you put water in the freezer and leave it overnight without adding anything else, it is highly likely that the water will freeze. The freezer's primary function is to lower the temperature below the freezing point of water, typically around 0°C (32°F). Consequently, water left in the freezer will eventually freeze, given sufficient time.
To prevent water from freezing in the freezer, you would need to introduce an element that inhibits the freezing process, such as adding ice cubes or substances that lower the freezing point, like salt or antifreeze. These substances can lower the freezing point of water and potentially keep it in a liquid state at temperatures below 0°C (32°F).
However, it's important to note that altering the freezing point of water can have various effects on its usability or suitability for certain applications. Therefore, it's advisable to understand the specific purpose or requirements you have for keeping the water in a liquid state before attempting any modifications.