Phlegm

Noun

1. One of the four humors making up the body in ancient and mediaeval medicine; said to be cold and moist, and often identified with mucus. .mw-parser-output .defdate{font-size:smaller}
2. Viscid mucus produced by the body, later especially mucus expelled from the bronchial passages by coughing.
3. A watery distillation, especially one obtained from plant matter; an aqueous solution.
4. Calmness of temperament, composure; also seen negatively, sluggishness, indifference.
5. ↑ Douglas Harper (2001–2026), “phlegm”, in Online Etymology Dictionary.