What does it mean to be fearless?

Is there such a thing?
Since fearlessness lies entirely in the perception of the viewer, not the one acting fearless, is there such a thing? And does it matter?
When I was a kid and watched my neighbors go whooshing by on bikes, I thought they were so brave. I wanted to be them. But who knows what their hearts were thinking as they whizzed down the hill? Who knows what younger kids thought as I did the same thing a few years later? I certainly did not feel fearless!
In my job, I work with a lot of power tools and teach others to do the same. I know that fear is a good thing; it makes us pay attention and keeps us humble. A machine will let a user know, almost immediately, if they are doing something wrong. Fear of things going wrong keeps our heads in the game. This is not to say I enjoy being crippled by fear, (certainly no one does) but to dileniate between fearlessness and recklessness.
I guess, for me, it's about preparing as best possible, hoping for the best, giving my best. I don't want to miss out on something because I was afraid (like I almost did with bikes!).
I guess being fearless is following your dreams, being an (unintentional) inspiration for someone else. When your heart calls, it calls so loudly that it's hard to hear anything else. My suggestion: follow it. Follow it because in the end, it doesn't matter if there is such a thing as  being fearless because you are being the bright light you are and following your path, illuminating the path in the process, so that others may see the way to go.