Malaise is a feeling of general discomfort, uneasiness, or pain, often the first sign of an infection or other disease.  The word has existed in the French language since at least the 12th century.
The term is also often used figuratively in other contexts.
Malaise is a
non-specific symptom and can be present in the slightest ailment, such as an emotion (causing fainting, a vasovagal response) or hunger (light hypoglycemia ), to the most serious conditions (  cancer, stroke, heart attack, internal bleeding, etc.).
Malaise expresses a patient's uneasiness that "something is not right" that may need a medical examination to determine the significance.
Malaise is thought to be caused by the activation of an immune response, and the associated pro-inflammatory
Economic malaise" refers to an economy that is stagnant or in recession (compare depression). The term is particularly associated with the US 1973-75 recession. A speech made by President  Jimmy Carter in 1979 is commonly referred to as the "malaise" speech, although the term was not in the speech. 
Notes and references
"Malaise: MedlinePlus Medical Encyclopedia". medlineplus.gov. Archived from the original on 2016-09-16.
"Well". Archived from the original on 2018-04-24 – via NYTimes.com.
Sommerfield, Andrew J.; Deary, Ian J.; McAulay, Vincent; Frier, Brian M. (1 February 2003). "Short-Term, Delayed, and Working Memory Are Impaired During Hypoglycemia in Individuals With Type 1 Diabetes". Diabetes Care. 26 (2): 390-396. doi: 10.2337/diacare.26.2.390. PMID 12547868. Archived from the original on 13 September 2016 – via care.diabetesjournals.org.
Dantzer, Robert (1 December 2016). "Cytokine, Sickness Behavior, and Depression". Immunology and allergy clinics of North America. 29 (2): 247-264. doi: 10.1016/j.iac.2009.02.002. ISSN 0889-8561. PMC . 2740752 PMID 19389580.
^ One example can be found in
The Next 200 Years: A Scenario for America and the World, by Herman Kahn et al., published in 1976, p. 2.
". Miller Center, University of Virginia. Archived from "Crisis of Confidence" Speech (July 15, 1979)" the original (text and video) on July 21, 2009.