chronic fatigue syndrome

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A syndrome characterized by debilitating fatigue and a combination of flulike symptoms such as sore throat, swollen lymph glands, low-grade fever, headaches, and muscle pain or weakness. Also called chronic fatigue immune dysfunction syndrome.

Wiktionary

1. n. pathology A condition characterized by immune, endocrine and neurologic pathology whose main symptoms are extreme fatigue, extremely low stamina, muscle pain, lymph node swelling, post-exertional Malaise, and cognitive difficulties.