stridency vs shrillness

stridency and shrillness both are nouns.

Word	Noun	Adjective	Verb	Adverb
stridency	Yes	No	No	No
shrillness	Yes	No	No	No

As nouns, stridency and shrillness are synonyms defined as:

stridency and shrillness: having the timbre of a loud high-pitched sound

Other synonyms of stridency include stridence.

stridency (noun)	shrillness (noun)
having the timbre of a loud high-pitched sound	having the timbre of a loud high-pitched sound
	the quality of being sharp or harsh to the senses