Zackass: an internet troll whose opinions are always more equal than others; one who will put you down because he has 'served his country' and believes that you have not; one who will never admit he is wrong, despite overwhelmingevidence to the contrary
Having extreme qualities of what it is to be a jackass, or something close to it. If someone around you is fucking around and acting like a dumbass, refer to him as a 'zackass'.
'When we were washing cars for a school fundraiserlast weekend, I told Zack to go and get the towels, so he decides to dance on them. *facepalm* what a zackass.'