insincerity vs falseness

insincerity and falseness both are nouns.

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

As nouns, insincerity and falseness are synonyms defined as:

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

Other synonyms of insincerity include hollowness.

insincerity (noun)	falseness (noun)
the quality of not being open or truthful; deceitful or hypocritical	the quality of not being open or truthful; deceitful or hypocritical
	unfaithfulness by virtue of being unreliable or treacherous
	the state of being false or untrue