My definition is someone who has failed — and blames others for her/his failure.
One of the best parts of Silicon Valley (and it certainly has its ugly parts) is that we embrace failure, up to a point. No one holds it against you if your first start-up failed (unless it lost a ton of money), or if an idea didn’t work out. No one.
But implicit in that is you’ll dust yourself off and either try again, or go join someone else’s venture.
If you just blame others for your failure — then, you are a failure.
You learned nothing, and have taken nothing from an experience to build on.