A massively fat individual, normally complete with gunt (f) windows apron (f) or giant belly (m) that's rather fond of wheelbarrow loads of deep fried potato products. When found in Scotland they are fairly recognisable by massive size and dark pink corned-beef pattern on skin.
"Chinpoko" (and also "chinpo") is a children's euphemism for "penis" in Japanese, much like "wee-wee" in American English. Chinpokomon originates from the words chinpoko and Pokémon Chinpokomon literally means Penis Monster(s).