A Flint Knapper is one who knows how to make tools out of Flint. While almost everybody has some basic knowledge of how to work the stone there are some who are considered to be "Masters" of their Craft. Some examples of these people are:
Dalanar - The man of Jondalar's hearth. He taught his two children, Joplaya and Jondalar how to knap flint. He was excited about the new flint knapping technniques Jondalar brought back with him.
Joplaya - Jondalar's close cousin. We only see her knapping flint once, and she ended up shattering her blade in surprise, but Jondalar claims that in some ways she is better at it than he.