The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 309

अथ यत्रैतत्पुरुषः पिपासाति नाम

In plain words

Now, when a person is in this state, he is said to be thirsty.

Close to the Sanskrit

Now, when a person is in this state, he is called thirsty.