Insincere :: Insincere (a.) Not being in truth what one appears to be; not sincere; dissembling; hypocritical; disingenuous; deceitful; false; -- said of persons; also of speech, thought; etc.; as, insincere declarations..
Insincerity :: Insincerity (n.) The quality of being insincere; want of sincerity, or of being in reality what one appears to be; dissimulation; hypocritical; deceitfulness; hollowness; untrustworthiness; as, the insincerity of a professed friend; the insincerity of professions of regard..