1. Belief in the spirit, soul, often as it relates to religious, sacred, or otherwise noncorporeal matters. A little
metaphysics and philosophy are peripherally related as well, as its purpose is to give us perspective
on life and what to do with it.
2. The application of any sort of philosophy, however defined, regardless of whether the person in question has any spiritual beliefs or not. This use of the word is so vague that it can be redefined to mean anything, even something that is completely
materialistic.
I'm sorry, "belief in the laws of science" is not spirituality. "Realising your own inner
divinity" is not spirituality. "Being nice to people" is not spirituality. If you have no spiritual beliefs, you are not spiritual, simple as that.
Of course, one shouldn't be afraid to call oneself and atheist or agnostic. It doesn't mean you are shallow, immoral,
closed-minded,
intellectually dishonest, or anything of that sort.