phlegmatic (adj.)youdaoicibaDictYouDict[phlegmatic 词源字典]
"cool, calm, self-possessed," and in a more pejorative sense, "cold, dull, apathetic," 1570s, from literal sense "abounding in phlegm (as a bodily humor)" (mid-14c., fleumatik), from Old French fleumatique (13c., Modern French flegmatique), from Late Latin phlegmaticus, from Greek phlegmatikos "abounding in phlegm" (see phlegm).
A verry flewmatike man is in the body lustles, heuy and slow. [John of Trevisa, translation of Bartholomew de Glanville's "De proprietatibus rerum," 1398]
[phlegmatic etymology, phlegmatic origin, 英语词源]
self-possession (n.)youdaoicibaDictYouDict
"command of one's emotions," 1745, from self- + possession (n.). Related: Self-possessed.