phlegmatic (adj.)

mid-14c., fleumatik, "having the temperament formerly supposed to result from predominance of the bodily humor phlegm" (cool, calm, self-possessed, and in a pejorative sense, cold, dull, apathetic;) late 14c., "composed of phlegm (the bodily humor); containing phlegm," from Old French fleumatique (13c., Modern French flegmatique), from Late Latin phlegmaticus, from Greek phlegmatikos "abounding in phlegm" (see phlegm). Related: Phlegmatical; phlegmatically.

A verry flewmatike man is in the body lustles, heuy and slow. [Bartholomew Glanville, "De proprietatibus rerum," c. 1240, translated by John of Trevisa c. 1398]