If you were going to explain Dharmakāya to someone who has never encountered the topic prior, where would you begin?

Dharmakāya is tricky business to explain. If you were to explain it to someone who has never heard of the concept where would you begin? How does it fit in with attraction and aversion? At the same time the explainer would have to make sure to cover the different ways the word Dharmanakaya has been used.