Hardship qua thirst- A type of Pariṣaha (hardship);the pangs of thirst (which is likely to arise) on account of non-availability of drinking water is to be endured equanimously by the ascetic.
tao puṭṭho pivāsāe dognṃcchī lajjasamjae. sīodagaṃ na sevijjā viyaḍassesaṇaṃ care., chinnāvāesu paṃthesu ānre supivāsie. parisukkamuhe'dīṇe taṃ titikkhe parisahaṃ.
(U 2.4,5)