Lower body weight than normal

The answer is:  A term denoting the thinness of an adult and a decrease in weight to less than the normal and healthy weight range

Underweight is a condition in which body weight is lower than expected based on age, height, and gender. It can be caused by a variety of causes, including disease, poor diet, and unhealthy lifestyle choices. It is important to treat this condition in order to maintain good health. A safe and healthy weight loss goal should be to reduce body weight by 10% in 6 months or less. It is important to note that a weight loss diet or exercise program should result in a body weight reduction of 0.45-2 kg (1-4 lbs) per week. To achieve this goal, it is best to consult a healthcare professional for advice on the best diet or exercise program for you. Taking into account your individual circumstances, they can help you set realistic goals and provide support throughout the process.