From Longman Dictionary of Contemporary Englishinsincerein‧sin‧cere /ˌɪnsɪnˈsɪə◂ $ -ˈsɪr◂/ ●○○ adjective PRETENDpretending to be pleased, sympathetic etc, especially by saying nice things, but not really meaning what you say an insincere smile an offer which she knew to be impractical and insincere —insincerely adverb —insincerity /ˌɪnsɪnˈserəti/ noun [uncountable]
Examples from the Corpus
insincere• The mayor's sympathy seemed insincere.• an insincere compliment• He always praised everyone, so it was difficult to tell if he was being insincere or not.• 'It's so good to see you again, ' she said, with an insincere smile. 