Antonyms of adj sincere

2 senses of sincere

Sense 1
sincere (vs. insincere) -- (open and genuine; not deceitful; "he was a good man, decent and sincere"; "felt sincere regret that they were leaving"; "sincere friendship")

insincere (vs. sincere) -- (lacking sincerity; "a charming but thoroughly insincere woman"; "their praise was extravagant and insincere")
        => bootlicking, fawning, obsequious, sycophantic, toadyish -- (attempting to win favor from influential people by flattery)
        => buttery, fulsome, oily, oleaginous, smarmy, soapy, unctuous -- (unpleasantly and excessively suave or ingratiating in manner or speech; "buttery praise"; "gave him a fulsome introduction"; "an oily sycophantic press agent"; "oleaginous hypocrisy"; "smarmy self-importance"; "the unctuous Uriah Heep"; "soapy compliments")
        => dissimulative -- (concealing under a false appearance with the intent to deceive; "dissimulative arts")
        => false -- (deliberately deceptive; "false pretenses")
        => feigned -- (not genuine; "feigned sympathy")
        => gilded, meretricious, specious -- (based on pretense; deceptively pleasing; "the gilded and perfumed but inwardly rotten nobility"; "meretricious praise"; "a meretricious argument")
        => hypocritical -- (professing feelings or virtues one does not have; "hypocritical praise")
        => plausible -- (given to or characterized by presenting specious arguments; "a plausible liar")

Sense 2
earnest, sincere, solemn -- (characterized by a firm and humorless belief in the validity of your opinions; "both sides were deeply in earnest, even passionate"; "an entirely sincere and cruel tyrant"; "a film with a solemn social message")

INDIRECT (VIA serious) -> frivolous -- (not serious in content or attitude or behavior; "a frivolous novel"; "a frivolous remark"; "a frivolous young woman")

Similarity of adj sincere

2 senses of sincere

Sense 1
sincere (vs. insincere) -- (open and genuine; not deceitful; "he was a good man, decent and sincere"; "felt sincere regret that they were leaving"; "sincere friendship")
       => bona fide -- (undertaken in good faith; "a bona fide offer")
       => cordial -- (sincerely or intensely felt; "a cordial regard for his visitor's comfort"; "a cordial abhorrence of waste")
       => dear, devout, earnest, heartfelt -- (earnest; "one's dearest wish"; "devout wishes for their success"; "heartfelt condolences")
       => honest -- (without dissimulation; frank; "my honest opinion")
       => genuine, true (prenominal), unfeigned -- (not pretended; sincerely felt or expressed; "genuine emotion"; "her interest in people was unfeigned"; "true grief")
       => heart-whole, wholehearted, whole-souled -- (with unconditional and enthusiastic devotion; "heart-whole friendship"; "gave wholehearted support to her candidacy"; "wholehearted commitment"; "demonstrated his whole-souled allegiance")
          Also See-> genuine#1, echt#1; honest#1, honorable#1; ingenuous#1, artless#1; real#1, existent#2; true#1

Sense 2
earnest, sincere, solemn -- (characterized by a firm and humorless belief in the validity of your opinions; "both sides were deeply in earnest, even passionate"; "an entirely sincere and cruel tyrant"; "a film with a solemn social message")
       => serious (vs. frivolous) -- (concerned with work or important matters rather than play or trivialities; "a serious student of history"; "a serious attempt to learn to ski"; "gave me a serious look"; "a serious young man"; "are you serious or joking?"; "Don't be so serious!")