sincerity vs insincere

sincerity is a noun but insincere is not a noun.

Word	Noun	Adjective	Verb	Adverb
sincerity	Yes	No	No	No
insincere	No	Yes	No	No

sincerity (noun)	insincere (noun)
the quality of being open and truthful; not deceitful or hypocritical
the trait of being serious
a quality of naturalness and simplicity
an earnest and sincere feeling

sincerity (adjective)	insincere (adjective)
	lacking sincerity