A common Jewish nickname.
Sean: What's your name
Sean: Damn! you are a kike!
A heshie is what you call a person when you don't know whether they are a he or she so you call them a heshie.
Person 1 - Is that a he or a she?
Person 2 - I dunno..must be a heshie.
Person 1 - Ohhhh I see