insincerity vs hollowness

insincerity and hollowness both are nouns.

Word	Noun	Adjective	Verb	Adverb
insincerity	Yes	No	No	No
hollowness	Yes	No	No	No

As nouns, insincerity and hollowness are synonyms defined as:

insincerity and hollowness: the quality of not being open or truthful; deceitful or hypocritical

Other synonyms of insincerity include falseness.

insincerity (noun)	hollowness (noun)
the quality of not being open or truthful; deceitful or hypocritical	the property of having a sunken area
	the quality of not being open or truthful; deceitful or hypocritical
	the state of being hollow: having an empty space within