谄笑: ingratiating smile; fawning smile, flattery smile
真笑: True smile, genuine smile
假笑: feign smile, fake smile
佯笑:feign smile,fake smile
龋齿笑 flattery smile as if teeth pain. (笑起来好像牙齿疼、满脸不高兴的样子。)語本後漢書.卷三十四.梁統傳:「壽色美而善為妖態,作愁眉,嗁妝,墮馬髻,折腰步,齲齒笑,以為媚惑。」
各位大神请拍砖!