1 the thick viscous substance secreted by the mucous membranes of the respiratory passages, discharged by coughing.
2 a coolness and calmness of disposition. b sluggishness or apathy (supposed to result from too much phlegm in the constitution).
3 archaic phlegm regarded as one of the four bodily humours.
Derivatives:
phlegmy adj.
Etymology: ME & OF fleume f. LL phlegma f. Gk phlegma -atos inflammation f. phlego burn
Useful english dictionary. 2012.