Refers to physical thirst or a strong desire for something. Often used in compounds like 渇望 (かつぼう, craving) or 渇水 (かっすい, water shortage).
I drink water to quench my thirst.
He satisfied his thirst for knowledge by reading books.
craving; longing; thirsting
water shortage; low-water condition
thirst; dry mouth
cessation of coughing
The kanji 渇 is composed of 氵(water) and 曷 (phonetic component), originally meaning 'dry up' or 'thirst'. The reading かつ is the on'yomi.