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.

Healthy individuals had more of these bacteria than people with conditions such as inflammatory bowel disease, obesity, and chronic fatigue syndrome.

From Science Daily • Feb. 14, 2026

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

Diagnosed with chronic fatigue syndrome, as well as Pots - a condition which causes dizziness - and hypermobility, she struggled with attendance and anxiety.

From BBC • Aug. 13, 2025

Ms Beck, 63, who suffers from myalgic encephalomyelitis, which is also known as chronic fatigue syndrome, said she had planned to visit the area soon.

From BBC • Apr. 12, 2025

There are eating disorders, shingles, skin problems, kidney disease, Alzheimer's, senility, mental illness, addictions, chronic fatigue syndrome, aids.

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