falseness vs insincerity

falseness and insincerity both are nouns.

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

As nouns, falseness and insincerity are synonyms defined as:

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

Other synonyms of falseness include hollowness.

falseness (noun)	insincerity (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