What does the phrase burnout mean? Have you experienced it? What does it feel like?

All energy/fuel used up – do you mean mental burn out or the 'bonk', where you ride too long without eating?

It's like depression with work. It's crap.

If you mean in a work/creative context I guess it means all of "it" has gone, no more ideas, energy to create new ideas, cannot make headway in any direction as if you never could.
Not experienced that, but can imagine it.

Nervous exhaustion..?

I thought it was what you did in a car when you rev the nuts off it and dump the clutch?

Wheelspin = burnout?

Well that's what it meant when I was a kid anyway…..

When someone you don't like hides in a good little hole. You burnout the bugger.

So, to set fire to the safe haven of an adversary.