Someone who doesn't know the difference between being cool/thug/badass and being a jerk/idiot/asshole/coward. A person who will most likely stay a loser for the rest of his life if he doesn't learn the difference.
A loser who tries to stand out by doing idiotic/dangerous/harmful things and thinks that they make him look cool.
A wannabe thug who's really a lugnut or idiot.
A portmanteau of the insult "lugnut" and the term "thug". Also, the word "nut" is similar to the word "not", implying that the person is not really a thug. Also implies that they are about as badass as a real thug's left nut.
Wearing thug clothes, acting like an asshole, and picking on people doesn't make you cool. You're a thugnut, a poser, and a coward.
That thugnut who hit that teacher is going to jail. What a way to show you're tough by hiding behind your friends and punching an innocent person.