1. Gnarled, disgusting, twisted, dangerous, etc.
2. Slang. Cool or excellent.
Not much is known about this primitive creature from a more primal age, but some things can be gathered by cave paintings and the creatures own nonsensical jabbering.; millenia ago, Gnar was just a yordle boy when a great evil threatened his tribe, and he rose up to defeat it with his bone boomerang. For some reason, perhaps by the creature or by his own people, the boy was frozen in true ice. Vacantly, he stared on the wastes of Valoran as time marched on before him, and yet, not even such magic could contain the beast within. After escaping the ice, the creature wandered Runeterra until he was taken in by some yordles. It did not take long for them to learn that the boy...
But, he is pretty easy to forgive, being the cutest champion in League of Legends-- I mean his alt skin has the little creature, a mix between a fennec fox, a mogwai and Taz the Tasmanian Devil, wearing dinosaur footie pajamas!
For the rest of this break down, we will refer to his default form as mini Gnar.