He glanced at her slyly.

他诡秘地朝她瞥了一眼。

《牛津词典》

Anna grinned slyly.

安娜会意地咧嘴笑了。

《柯林斯英汉双解大词典》

Some one must have slipped it slyly into my pocket for a joke.

一定是有人捉弄我，偷偷地把它塞进了我的口袋。

youdao

When Moon fancies himself a movie-style hitman, Chan slyly slips into pop video mode.

CNN: Hong Kong's Unknown Face

He seems puzzled a lot of the time, a little slow, though slyly amused around women.

NEWYORKER: No Strings Attached

Since 2006, Kavarna has slyly dubbed itself 'capital of rock', largely due to its annual Rock Fest.

BBC: The Black Sea by Moskvitch