Many people will use words like "spiritual" and "spirituality" like they were common everyday words, like it's completely clear to anybody what they mean. However, try to ask someone what they mean by "spiritual", and you might find out that, even to their own surprise, they cannot clearly define it. (In a significant amount of cases they will even retort something like "you know perfectly well what it means", rather than trying to answer.)
I just had an epiphany: When for example reading any text that uses eg. the word "spiritual" (that's not just discussing said word in a rational skeptic manner), simply substitute it with the word "emotional". Suddenly all that text starts making much more sense!
For example, "that was a very spiritual experience" = "that was a very emotional experience."
"My spirit was moved" = "my emotions were moved."
"She's a very spiritual woman" = "she's a very emotional woman."
"You couldn't even begin to understand the spiritual world" = "you couldn't even begin to understand the emotional world."
It just fits so perfectly!
(And that's really what "spiritual" means: Emotional. It's all about feelings and emotions, nothing more. All those sentences start making a lot more sense this way.)