impassiveness vs emotionlessness

impassiveness and emotionlessness both are nouns.

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

As nouns, impassiveness and emotionlessness are synonyms defined as:

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

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

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