quietness vs tranquility

quietness and tranquility both are nouns.

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

As nouns, quietness and tranquility are synonyms defined as:

Other synonyms of quietness include quietude, tranquillity.

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