The crossword solution for the term 'waterproof again' is 'reseal, ' which is a six-letter word. Resealing is the process of making something waterproof again by applying a new sealant or coating to it. This can be done to a variety of items, such as windows, doors, and other surfaces, to prevent water from entering. Resealing is often used to repair existing waterproofing that has been damaged or worn away over time.