Definition of Tired

Tired: A feeling of a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a sense of weariness and fatigue.

Tiredness is not a singular symptom that defines any one particular disease. Rather, tiredness can be a symptom of many different diseases and conditions. The causes of tiredness range from lack of sleep or excessive exercise to significant medical and surgical problems.

The lack of energy associated with tiredness can sometimes cause difficulty with normal daily activities, leading to problems with attentiveness and concentration.