sly

蛇在树叶间显得很狡猾。

The snake looks ___sly among the foliage.

他偷偷地眨了眨眼睛，露出一个调皮的笑容。

He gave me a ___sly wink with a mischievous grin.

他狡黠地眨了眨眼，暗示他知道秘密。

He gave me a ___sly wink to show he knew the secret.