Alternative spelling of willy
"The old cartoon character Willie was just an alternative spelling of Willy in some versions of the story."
"Willie is my best friend who always knows how to have fun."
A diminutive of the male given name William
"Willie waved goodbye to his older brother, who had just left on a trip to London."
Willie is a familiar form of the name William created by adding the diminutive suffix "-ie." This affectionate nickname has been used in English since at least the late 16th century to refer to boys named William or as an independent given name.