Lacking hydration is a term used to describe a state of dehydration, which occurs when the body does not have enough water or fluids. ARID is a four-letter word that is often used to describe this state, as it means 'extremely dry.' When the body is lacking hydration, it can lead to a variety of health issues, such as fatigue, headaches, and dizziness. It is important to stay hydrated in order to maintain good health.