1. One of the four humors of which the ancients supposed the blood to be composed. See Humor.
2. (Science: physiology) viscid mucus secreted in abnormal quantity in the respiratory and digestive passages.
3. (Science: chemistry) A watery distilled liquor, in distinction from a spirituous liquor.
4. Sluggishness of temperament; dullness; want of interest; indifference; coldness. They judge with fury, but they write with phlegm. (pope)
Origin: F. Phlegme, flegme, L. Phlegma, fr. Gr. A flame, inflammation, phlegm, a morbid, clammy humor in the body, fr. To burn. Cf. Phlox, Flagrant, Flame, Bleak, and Fluminate.