What does Kompaan mean?

"Hey kompaan, come sit with us," he called from the couch.

Dutch student slang. This is a Dutch word. You will hear it a lot at Dutch universities, student associations and in student houses.

It is mostly used among friends as a casual, friendly way to address someone. A bit old-fashioned, a bit funny. Like calling someone "comrade" with a wink. Also read about gozer and maat.