impassiveness vs unemotionality

impassiveness and unemotionality both are nouns.

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

As nouns, impassiveness and unemotionality are synonyms defined as:

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

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

impassiveness (noun)	unemotionality (noun)
apathy demonstrated by an absence of emotional reactions	absence of emotion
	apathy demonstrated by an absence of emotional reactions