The term 'Went Under' can be used to describe a variety of different scenarios. It can mean that something dove, sank, SUNK, FAILED, or dived. In each case, the object in question is going below the surface of something, such as water or a situation. For example, if a boat dove, it would be going under the surface of the water. If a business sank, it would be going under financially. If a person FAILED, they would be going under the expectations of their peers. If a person dived, they would be going under the surface of the water. In all cases, the term 'Went Under' implies that something is going below the surface of something else.