"Hie" Is a way to say hello, But in a new cool way said. It was once happened when a person typed "Hie" at one time and it went everywhere, People started saying hie.
Hie is a common typo of the word "hoe" it means you are a hoe of supreme hoeness so much that just the word 'hoe' isn't enough to describe it so HIE is hoe to the 2nd power.