A Hitmonchan is said to possess the spirit of a boxer who aimed to become the world champion. Having an indomitable spirit means that it will never give up.
(From Bulbapedia) Hitmonchan is a tan, humanoid Pokémon that is exclusively male. There are five blunt protrusions on top of its head, and it has extensions resembling pads over its shoulders. It appears to be wearing a light purple tunic and kilt, as well as red boxing gloves and light purple boxing shoes. As this appearance suggests, Hitmonchan specializes in punching. It is able to throw punches too quick to be seen with the naked eye. By punching with a corkscrew motion, it is even capable of drilling through concrete. However, Hitmonchan requires a break every three minutes while fighting. Despite the need for frequent breaks, it has an unwavering spirit and will never give up in a difficult situation. Usually found in urban areas, it is rarely seen in the wild.
(From Bulbapedia) Hitmonchan may be a personification of boxing. The colors of Hitmonchan's gloves in its normal and Shiny colorations are a reference to the red corner and blue corner in boxing. Its Gold, HeartGold, Generation V, and X Pokédex entries mention that it needs a short break after fighting for three minutes, which is a reference to the duration of rounds in boxing.
(From Bulbapedia) Hitmonchan is a combination of hit, monster, and Chan (a reference to Jackie Chan). The name is also related to Tyrogue's other evolutions, Hitmonlee and Hitmontop.