The Kenosis is a teaching concerning Jesus' incarnation. The Kenosis attempts to solve some paradoxes between the nature of God and of man as united in Jesus. For example, how could an all knowing God become a baby, or how could God be tempted? The Kenosis maintains that God, when becoming a man, divested Himself of some qualities of being a man.
In a sense, the Kenosis is God minus something; God subtracting some qualities of deity to become a man. The Hypostatic Union is God plus something; God adding human nature to Himself. The Kenosis, then, jeopardizes the true incarnation because it puts in doubt the full indwelling of God among men in the person of Jesus. (Compare with Hypostatic Union.)