St. Anselm (1033-1109 AD) had a well-known motto— “fides quaerens intellectum.” This is Latin and translates as “Faith Seeking Understanding.” This can be seen as a good explanation of Theology. I believe that Theology must draw from a place of Faith. One can study Christian Theology without having Christian faith. However, that should be thought of as Religious Studies. To DO Christian Theology, one must have the Christian Faith and thus doing Christian Theology involves one seeking to relate reason and understanding to that Faith.
That works for Biblical Theology and for Systematic Theology. I suppose that works fairly well to Historical Theology and Philosophical/Natural Theology as well. However, in Practical Theology, the description needs to church. This includes Homiletics, Theology of Worship, Missiology, and more.
For these, I would say, it is the Practice of Faith Seeking Understanding. It deals with the Whats of Practice as well as the Whys.
I don’t know Latin, but I tried a translator program for “The Practice of Faith Seeking Understanding” and it said,
Praxis Fidei Quaerens Intellectus
If someone knows Latn, I would welcome corrections or improvements on this. In general, Mission Theology would be The Practice of Faith (relating to Missions) Seeking understanding.