phlegm vs stolidity

phlegm and stolidity both are nouns.

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

As nouns, phlegm and stolidity are synonyms defined as:

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

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

phlegm (noun)	stolidity (noun)
inactivity; showing an unusual lack of energy	an indifference to pleasure or pain
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
apathy demonstrated by an absence of emotional reactions