他脸上露出阴险的笑容，让人不寒而栗。

He gave a ___sinister smile that sent chills down my spine.

他的笑容背后隐藏着邪恶的意图。

There was a ___sinister motive behind his friendly smile.

他脸上那种阴险的笑容让我感到不安。

The ___sinister smile on his face made me feel uneasy.