Definition of "burn out"

burn out

verb
third-person singular simple present burns out, present participle burning out, simple past and past participle burned out or (mostly Commonwealth) burnt out
1. (transitive) To destroy by fire.
  Quotations
  All four engines and the entire train were derailed, and owing to the fact that all the vehicles except the sleeping cars were gas-lit, the whole of the coaching stock except the two rear brakes was burned out, beginning with the two front coaches, which were completely wrecked.
  1941 April, “The Why and the Wherefore: Hawes Junction Collision”, in Railway Magazine, page 191 (the collision occurred in 1910)
2. (intransitive) To become extinguished due to lack of fuel.
  Quotations
  Mr. Mason, shivering as some one chanced to open the door, asked for more coal to be put on the fire, which had burnt out its flame, though its mass of cinder still shone hot and red. The footman who brought the coal, in going out, stopped near Mr. Eshton's chair, and said something to him in a low voice, of which I heard only the words, "old woman,"—"quite troublesome."
  1847, Charlotte Brontë, Jane Eyre, Chapter XVIII
3. (intransitive) To become nonfunctional (especially of lightbulbs or similar light-producing devices).
4. (intransitive) To tire due to overwork; to overwork to their limit.
5. (transitive) To cause (someone) to tire due to overwork; to cause (someone) to overwork to one's limit.
6. (intransitive, slang, uncommon) To end one's shift at a job.
7. (intransitive, automotive) To have one's tires skid against the ground; to peel off, peel out.
8. (idiomatic) To make (someone) unavailable for work involving exposure to ionizing radiation by employing (the person) in such work until the person's accumulated exposure reaches the maximum permitted for an administrative period, typically a year.
noun
uncountable
1. (idiomatic) (of a person) The condition of tiredness due to overwork.
  Quotations
  His burn out hadn't been caused by too many dead bodies; it was from spending his life doing for people what most of them had refused to do for themselves.
  2002, Chuck Purdy, The Street Saint: Emergency in the Emergency Services‎