tautness vs tightness

tautness and tightness both are nouns.

Word	Noun	Adjective	Verb	Adverb
tautness	Yes	No	No	No
tightness	Yes	No	No	No

As nouns, tautness and tightness are synonyms defined as:

tautness (noun)	tightness (noun)
lack of movement or room for movement	lack of movement or room for movement
the physical condition of being stretched or strained	extreme stinginess
	the spatial property of being crowded together
	a tight feeling in some part of the body
	a state occasioned by scarcity of money and a shortage of credit