As a Noun: 1. A medical condition of unknown cause, with fever, aching, and prolonged tiredness and depression, often occurring after a viral infection. English = chronic fatigue syndrome, CFS. Note: 1. There appears to be no commonly used Auslan sign for CHRONIC FATIGUE SYNDROME. If you know a sign for CHRONIC FATIGUE SYNDROME used by you or other Auslan users (deaf people or interpreters) please go to "report missing sign" and supply details. Thank you.