0 to move towards someone: --
1 to be mentioned or talked about in conversation: --
2 When the sun or moon comes up, it rises. --
3 If a job or opportunity comes up, it becomes available: --
A position has come up in the accounts department.
4 to happen, usually unexpectedly: --
5 to be mentioned or talked about in conversation: --
If the subject of divorce comes up, try to change the subject.
He came up to me at a party and introduced himself.
He just came up to me and punched me.