go under

Short definition from Wiktionary

Verb

1. 1
   To descend into a body of water; to founder.
2. 2
   To collapse or fail, e.g. by going bankrupt.
3. 3
   To die.
4. 4
   To be named; to call oneself.
5. 5
   To enter a trance, state of hypnosis, etc.
6. 6
   To be imprisoned.