枯渇 (こかつ) uses the on'yomi 枯 (コ) meaning to wither/dry up, and 渇 (カツ) meaning to thirst/dry up. Both convey the sense of depletion. Incorrect readings like こひつ, こたん, and こしゃく are all misreadings of 渇. It refers to the complete exhaustion or drying up of something, whether literally (e.g., a well) or figuratively (e.g., resources, ideas).

枯渇（こかつ）は両漢字とも音読み。枯（コ）は「かれる」、渇（カツ）は「かわく」の意味。こひつ・こたん・こしゃくはすべて渇の誤読です。水が枯れるように、物資や資源がすっかり尽きてなくなる状態を指します。