Definition of the word ill humour

The phrase "ill humor" or "ill humour" (spelled with an "our" in British English) can be traced back to the Latin word "humor," which was used by ancient medical practitioners to describe the bodily fluids believed to be responsible for carrying heat and moisture throughout the body. These fluids included blood, phlegm, black bile, and yellow bile, and it was thought that an imbalance in these fluids could result in various physical and emotional conditions. The idea of humorism, as this system of medicine was called, fell out of favor in the 19th century as new scientific discoveries and insights replaced it with more modern diagnostic techniques and treatments. However, the word "humour" (again, spelled with an "our") and its variations continued to be used to describe an individual's state of mind, particularly when that state is negative or unpleasant. Thus, "ill humor" - which appeared in print as early as the 16th century - referred to a person who was in a disagreeable or ill-tempered mood, often associated with an imbalance in one of the four bodily fluids. The use of the word "ill" to describe such a mood also connoted a health issue, as it was believed in those days that emotional and physical ailments were closely intertwined. While the modern medical community no longer subscribes to the concept of humorism, the word "humour" (and its spelling variations) persist in colloquial speech as a synonym for mood, disposition, or personality trait. Similarly, "ill humour" (or "ill humor") continues to describe an individual's unfavourable or uncharacteristic state of mind, albeit with a more subtle connotation of its origin in the ancient medical theory.