stolidity vs impassiveness

stolidity and impassiveness both are nouns.

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

As nouns, stolidity and impassiveness are synonyms defined as:

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

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

stolidity (noun)	impassiveness (noun)
an indifference to pleasure or pain	apathy demonstrated by an absence of emotional reactions
apathy demonstrated by an absence of emotional reactions