Nailing jello to the wall

I don't know if spirituality is  the most difficult term to define, but you can spend a lot of time and find a lot of definitions.  Here are some I came across, with my working definition at the end.

Dictionary

spir·it·u·al·i·ty
ˌspiriCHo͞oˈalədē/
noun
noun: spirituality; plural noun: spiritualities
the quality of being concerned with the human spirit or soul as opposed to material or physical things.
"the shift in priorities allows us to embrace our spirituality in a more profound way"

Sr. Sandra M. Schneiders, I.H.M., Jesuit School of Theology at Berkeley

The experience of consciously striving to integrate one's life in terms not of isolation and self-absorption but of self-transcendence toward the ultimate value one perceives.
Spirituality in the Academy, Theological Studies 50 (1989)

Urban dictionary

People who still want the mental crutch of Religion, but want to be as vague as possible about it so its harder to argue with their bullshit. These people generally lack the ability to form coherent logical arguments, struggle to think carefully and deeply about subjects and don't like the rules and restrictions imposed by Religion. Their position is so vague as to become difficult to argue against, allowing them to not only benefit from the mental crutch that usually is attached to religion, but hold a smug air of superiority that will piss off any reasonable critical thinker no end.

Fr. Ronald Rolheiser O.M.I

“Spirituality is more about whether or not we can sleep at night than about whether or not we go to church. It is about being integrated or falling apart, about being within community or being lonely, about being in harmony with Mother Earth or being alienated from her. Irrespective of whether or not we let ourselves be consciously shaped by any explicit religious idea, we act in ways that leave us either healthy or unhealthy, loving or bitter. What shapes our actions is our spirituality. And what shapes our actions is basically what shapes our desire. Desire makes us act and when we act what we do will either lead to a greater integration or disintegration within our personalities, minds, and bodies—and to the strengthening or deterioration of our relationship to God, others, and the cosmic world. The habits and disciplines5 we use to shape our desire form the basis for a spirituality, regardless of whether these have an explicit religious dimension to them or even whether they are consciously expressed at all. Spirituality concerns what we do with desire. It takes its root in the eros inside of us and it is all about how we shape and discipline that eros. John of the Cross, the great Spanish mystic, begins his famous treatment of the soul’s journey with the words: 

“One dark night, fired by love’s urgent longings.” 

For him, it is urgent longings, eros, that are the starting point of the spiritual life and, in his view, spirituality, essentially defined, is how we handle that eros.”
The Holy Longing: The Search for a Christian Spirituality

Colleen M. Griffith, Boston College

From a Christian perspective, spirituality gets traced back to the letters of Paul in which he uses the Greek term pneuma to signal a life lived in alignment with God’s Spirit. Christian spirituality presumes, through God’s grace, a human desire and capacity for growing in union with the Triune God. It encompasses the dynamic character of human life lived in conscious relationship with God in Christ through the Spirit, as experienced within a community of believers. To live a Christian spirituality is to attend to what is of God and to deepen in a life of conversion that has discipleship as its goal.
Christian Spirituality in Practice, Century 21 Resources, Spring 2009

And now me. This is subject to change, which I will try to be transparent about

Our individual pilgrimage responding to our deepest God given desires.
This is a difficult journey of integration and transformation to become our true selves doing our true work according to God’s loving intention for us.

So far, so good.