I understand the aversion some have to using the word "spiritual."
But if you think about it in terms of say, having spirit, I think it could take on an acceptable meaning for me.
My definition:
Spiritual: of, relating to, being in high spirits.
When I meditate, it is a spiritual experience in that sense. I feel refreshed, renewed and my mind feels centered - my spirits are high.
Spiritual, when relating to your mind, in this sense is acceptable to me.
However, if it has anything to do with something outside the physical universe, like some kind of detached being, or that there's something innate in you that is your "spirit," I reject that definition outright for lack of evidence.