1. Falling; happening or coming to pass without design in the person or persons affected, and without being foreseen, or expected; accidental; fortuitous; coming by chance; as, the parties had a casual rencounter.
2. Occasional; coming at certain times, without regularity, in distinction from stated, or regular; as casual expenses.
3. Taking place, or beginning to exist without an efficient intelligent cause, and without design.
Atheists assert that the existence of things is casual