Definition of phlegm

• a. - One of the four humors of which the ancients supposed the blood to be composed. See Humor.
• a. - Viscid mucus secreted in abnormal quantity in the respiratory and digestive passages.
• a. - A watery distilled liquor, in distinction from a spirituous liquor.
• a. - Sluggishness of temperament; dullness; want of interest; indifference; coldness.