cheeky
Definitions
Impudent or irreverent, typically in an endearing or amusing way.
Showing a lack of respect or proper manners in a playful or bold manner.
Examples
The cheeky child hid his mother's keys just to see her reaction.
He gave me a cheeky grin after winning the game by a narrow margin.
Synonyms
impudent audacious brazen impertinent sassy flippant presumptuous