Definition from Wiktionary, the free dictionary
- to descend into a body of water
- the boat was too heavy and went under.
- (idiomatic) to be named, to call oneself
- He goes under the name of Mr X to remain anonymous.
- (idiomatic) to go bankrupt, to collapse
- In the crisis, the company was forced to reduce its costs in order to avoid going under.
- to enter a state of hypnosis