Polydipsia
Polydipsia is excessive thirst or excess drinking. The word derives from the Greek πολυδίψιος (poludípsios) "very thirsty", which is gotten from πολύς (polús, "much, many") + δίψα (dípsa, "thirst"). Polydipsia is a symptom in many diseases. It also occurs as a weird behaviour in some animals, such as in birds.