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