Nimbleosity is a state of lightness.
A camera bag that weighs less than others has a high nimbleosity rating. My Olympus OM-D with F/1.8 lens is more nimble than my Canon 5D Mark II with the 35mm F/1.4 lens. The Olympus is both lighter and smaller than the Canon.
Nimbleosity Is also about using less. Why should I pack four pairs of shoes while traveling when two will serve me well? Do I really need to carry seven camera lenses? And can I get by with an iPad, instead of a computer, a mouse, hard drives, and power brick?
But most importantly, nimbleosity is a state of mind. "Angels fly because they take themselves lightly." Children often learn faster than adults because they don't have the image of intelligence to maintain.
There are things we need to take seriously: our responsibilities, our family, our friends. But not ourselves. We can create more with a light heart because we are free to experiment. So packing a small camera bag is only the first step toward nimbleosity. Moving lightly through the world is when the real magic begins.