GOBOSH is an acronym which stands for 'Go Big Or Stay Home.' No, I don't know what the origin is, although I imagine it is well-used in very macho communities.
It is also a company which manufactures and sells light sport airplanes under the 'Gobosh' name. They explicitly reference this acronym as the source of their name. Based in Moline, Illinois this firm has been producing aircraft with a Czech manufacturing partner since 2007; their product line at present seems to consist of two models. The Gobosh 700 series is an all-metal low-winged two-seat light sport airplane. The 800 series is an all carbon fiber composite version of the same airplane - lighter, faster, slightly higher useful load and payload.
As light sport airplanes, these aircraft may be operated in the US by pilots holding a sport pilot certificate, which is less rigorous than a private pilot certificate but comes with restrictions on the types of airplanes and airspace that the pilot may operate in.