phlegm

noun

1. 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.

2. 2

   Viscid mucus produced by the body, later especially mucus expelled from the bronchial passages by coughing.

3. 3

   A watery distillation, especially one obtained from plant matter; an aqueous solution.

4. 4

   Calmness of temperament, composure; also seen negatively, sluggishness, indifference.