General:
* Dehydration: This refers to a lack of water in the body, which can be caused by various factors.
* Aridity: This refers to a lack of water in a particular area, typically a desert or semi-desert environment.
* Drought: This refers to a prolonged period of abnormally low rainfall, resulting in a shortage of water.
Specific:
* Desiccation: This refers to the process of becoming completely dry, often used in the context of plants or soil.
* Thirst: This refers to the physiological sensation of needing water.
The best word to use will depend on the specific situation you are describing.