(n.) a term for a young African-American male residing in an urban environment. The term is derived from the visual appearance of a nunchuck, which bears resemblance to said people: slender, black, associated with violence, and often chained together. This term is extremely derogatory, as it insults the physique, nature, and history of the described people.
When a tibia and fibula both break and the person takes weight off that leg and the lower section of the leg swings like a nunchuck they have suffered what can only be medically described as 'Nunchuck Leg'
Connor McGregor went to take a step back, as he takes weight off his leg it's obviously broken by the way it swings like a nunchuck - he has suffered Nunchuck Leg