The term COVER-UP DURING A SHOWER can be summarized as the use of a tarp (4 letters). A tarp is a large sheet of waterproof material, usually made of plastic or canvas, that is used to cover objects or surfaces to protect them from the elements. It is commonly used to cover items such as boats, cars, and furniture, but it can also be used to cover up during a shower. This is especially useful for outdoor showers, where a tarp can provide privacy and protection from the rain.