Definitions

chronic fatigue syndrome

NOUN

disorder involving extreme fatigue and weakness

Synonyms

WEAK

chronic fatigue and immune dysfunction syndrome fatigue disease fatigue syndrome myalgic encephalomyelitis post-viral fatigue syndrome postviral syndrome yuppie flu

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The study included 57 people diagnosed with chronic fatigue syndrome and 25 healthy individuals of similar age and activity level.

From Science Daily • Nov. 10, 2025

Among the most common co-occurring illnesses were chronic fatigue syndrome and mast cell activation syndrome, or MCAS, a condition where patients experience intense episodes of diarrhea, hives, vomiting, and, in many cases, life-threatening anaphylaxis attacks.

From Slate • Sep. 15, 2025

It was reported that she suffered from a debilitating infection known as the Epstein Barr virus, and from the chronic fatigue syndrome, ME.

From BBC • Sep. 5, 2025

It is similar to chronic fatigue syndrome and can range from mild to debilitating.

From Los Angeles Times • Dec. 18, 2024

By giving the condition a name like "lymphoma" or "melanoma", "chronic fatigue syndrome" "Epstein-Barr syndrome" or "AIDS," "systemic yeast infection", "hepatitis" or what have, people think the doctor then understands their disease.

From How and When to Be Your Own Doctor by Solomon, Steve