- come upon, as if by accident; meet with (verb)
- I happened upon the most wonderful bakery not very far from here
- come into being; become reality (verb)
- come to pass (verb)
- What is happening?
- come about
- fall out
- go on
- pass off
- take place
- happen, occur, or be the case in the course of events or by chance (verb)
- It happens that today is my birthday
- chance to be or do something, without intention or causation (verb)
- I happen to have just what you need!
See definition of happen in Merriam Webster