Who is free from thirst in un-becoming, without desire in all un-becomings; disconnected from pleasures, that one is called Brahman.

Vibhava — un-becoming, annihilation, non-being. Even the desire to cease being is a form of thirst. Nihilism is thirst disguised.

The brāhmaṇa has transcended both eternalism (bhava) and nihilism (vibhava). One neither seeks to be, nor seeks not to be.