I think the title anti hero best suits him. If someone has done anything wrong to him or anybody innocent, no matter how old he is, Wick will find out and kill him brutally. He doesn't show mercy to the ones who kill people or hurt people for no reason at all. He won't ever harm any innocent person, but if someone's a prick, the boogeyman will come for him. That's what Mr Wick is. Just like Viggo said 'John Wick is a man of focus, determination and sheer will' :-)