Risk, the word itself sounds something vulnerable, it is the probability or threat of injury, damage, loss, liability or some negative occurrence which can be avoided with preventive approach.
Invention of steam power by James Watt, the British Scientist, was a landmark in power generation field since it gave a wing to human civilization to harness energy content of various fuels.
Imagine you have ordered a washing machine for your home, but when it arrives and you unbox it, the instructions manual is missing from the box. What happens then, if you try to install and run it without an instruction manual?