tranquillity vs quietness

tranquillity and quietness both are nouns.

Word	Noun	Adjective	Verb	Adverb
tranquillity	Yes	No	No	No
quietness	Yes	No	No	No

As nouns, tranquillity and quietness are synonyms defined as:

Other synonyms of tranquillity include quietude, tranquility.

tranquillity (noun)	quietness (noun)
a disposition free from stress or emotion	the property of making no sound
a state of peace and quiet	a state of peace and quiet
an untroubled state; free from disturbances