Definition
An impudent person, usually a child.
How People Actually Use It
Term used to define sexual our witty comment made in jest. Cheeky means you are flippant, have too much lip or are a bit of a smart arse! Generally you are considered to be a bit cheeky if you have an answer for everything and always have the last word.
"Cheeky - "Eee you cheeky monkey" was what my mother said to me all the time when I was a kid."
Source: Urban Dictionary