wickedly
In a playfully naughty or delightfully mischievous way.
Wickedly means in a way that is playfully mischievous or delightfully naughty. When your friend grins wickedly before telling a funny joke about the teacher, that expression shows they know they're being a little bit naughty but in a harmless, entertaining way. A character in a story might smile wickedly while planning a clever prank, or laugh wickedly after outsmarting someone.
A wickedly funny comedian makes jokes that are edgy and bold. A wickedly difficult puzzle is challenging in an almost unfair way, but not actually evil.
The word can also mean extremely or intensely, especially in casual speech. Someone might describe a roller coaster as wickedly fast or a winter day as wickedly cold. In Boston and some other parts of New England, people use wicked (without the “ly”) to mean “very”: wicked good ice cream or a wicked hard test.
When you see wickedly in a book, pay attention to the context. Is the character truly villainous, or just delightfully troublesome?