A man who is half Danish. A Halfdan is not, as some people think, someone who is 'half of a Dan'. Charactherized by the typical Danish love for beer, broad shoulders and a general viking-like physique. When a Halfdan is half Danish and half Norwegian this vikingness is particulary noticeable, and in addition his Norwegian half makes him extremely brainy.
Girl 1: Wow, that guy drinking beer has shoulders like a viking!
Girl 2: I bet he's a Halfdan!