Back in the era of World War II, a goldbrick was a slacker in the military. He was the guy who always seemed to be able to find a reason not to pull his own weight, as the phrase went.
The low-level Army grunts who wore the boots that were on the ground had a saying: "Never volunteer for anything." But you weren't supposed to be a slacker. Somewhere in between unofficial status as a red hot and a goldbrick was where most people wanted to be.
The term "goldbricking" has been extended to life outside the military. We read this on Wikipedia.
Goldbricking, in today's terms, generally refers to staff who use their work internet access for personal reasons while maintaining the appearance of working, which can lead to inefficiency. The term originates from the confidence trick of applying a gold coating to a brick of worthless metal.
Goldbricking is the creation of an illusion of value. The successful goldbrick keeps his employer in the dark about his productivity. He seems to be working. He isn't. He seems to be producing value. He isn't.
In business, people can hide in the shadows of the salary system. If you work 100% on commission, you can't hide. The reality of your output is measurable and objective. But salaried positions are not equally clear. Goldbricks operate in the zones of guesswork.