她巧妙地用玩笑掩饰了自己真正的意图，显示出狡黠的一面。

Her ___slyness was apparent as she cleverly hid her true intentions behind a joke.

他脸上带着顽皮的笑容，透露出一丝狡黠。

His playful grin showed a hint of ___slyness.