impassiveness vs phlegm

impassiveness and phlegm both are nouns.

Word	Noun	Adjective	Verb	Adverb
impassiveness	Yes	No	No	No
phlegm	Yes	No	No	No

As nouns, impassiveness and phlegm are synonyms defined as:

impassiveness and phlegm: apathy demonstrated by an absence of emotional reactions

Other synonyms of impassiveness include emotionlessness, impassivity, indifference, stolidity, unemotionality.

impassiveness (noun)	phlegm (noun)
apathy demonstrated by an absence of emotional reactions	inactivity; showing an unusual lack of energy
	expectorated matter; saliva mixed with discharges from the respiratory passages; in ancient and medieval physiology it was believed to cause sluggishness
	apathy demonstrated by an absence of emotional reactions