This is a phrase that's become common in the London skating scene, and generally refers to new skaters who don't yet have much in the way of skating skills. Howvever, it's still possible for experienced skaters to make gumbie-esque mistakes too.

A cultural and aesthetic mind-state that prioritizes making money, even as an “underground” or “radical” creator. The work isn’t made for money, but it’s the money that matters the most.

A dorky, or clumsy, or shy person. Like calling a person or yourself a gumbie is like making fun of their swag. like a person who is being a pussy about doing something like the example below.

A stupid person.

An ignorant person.

A large creature that resides in the realms of small room, eating large amounts of food substances and swears constantly. A gumbie will say fuck a total of 356 times per day.

Gumby - a Genetically Modified Being, similar to a GMO (Genetically Modified Organsim).

The exact definition of a genetically modified being and what constitutes genetic engineering varies, with the most common being an embryo born after being altered in a way that "does not occur naturally by mating and/or natural recombination of DNA".