a.

1. 狡猾的，狡诈的
   That sly girl managed to get her friend's job.

   那个诡诈的女孩设法取得她朋友的工作。

2. 诡秘的，悄悄的
   A slow sly smile was creeping around the corners of his mouth.

   他的嘴角慢慢露出了诡秘的微笑。

3. 会心的
   They exchanged sly looks and smiles.

   他们交换会意的眼色和微笑。

4. 恶作剧的，淘气的
   The sly cat stole the meat while the cook's back was turned.

   淘气的猫趁厨师转身之机偷吃了肉。

adj.

1. having a cunning and deceitful nature.
2. (of a remark, glance, or expression) insinuating.
3. (of an action) surreptitious.