言不由衷 [yán bù yóu zhōng]

• talk insincerely; a left-handed compliment; be insincere in one's words [speech]; not to say what one thinks in one's mind; not to speak honestly; One's heart is far from one's lips.; One's words belie one's mind.; say one thing and mean another; say what one does not mean; speak affectedly; speak without sincerity; speak with tongue in cheek; The words spoken are not from the heart.