Kear is the term to describe the 'abyss' that is between one and Dea; the separation that we have both as being a part of living in this existence, and the choices we make that move us further from Her. It is not sin as in Western Abrahamic faiths, it isn't a moral failing necessarily. Kear can also be described as ignorance or suffering, as with enough kear the effects are certainly felt as either or both of these things.
It is the abyss that can grow with poor choices that lead to poor outcomes, but can be lessened by living one's life in accordance with both Thamë and making good choices when we have to make decisions. When we live in accordance with Thamë and strive towards improving ourselves, we lessen our kear and the world at large's kear.