1. an undesirable or unfortunate happening that occurs unintentionally and usually results in harm, injury, damage, or loss; casualty; mishap: automobile accidents.
2. Law. such a happening resulting in injury that is in no way the fault of the injured person for which compensation or indemnity is legally sought.
3. any event that happens unexpectedly, without a deliberate plan or cause.
4. chance; fortune; luck: I was there by accident.
5. a fortuitous circumstance, quality, or characteristic: an accident of birth.
6. Philosophy. any entity or event contingent upon the existence of something else.
7. Geology. a surface irregularity, usually on a small scale, the reason for which is not apparent.
Having been the "injured person" in an "accident" which was " in no way the fault" of myself, just 4 months ago, I can certainly agree that it is "an undesirable or unfortunate happening". I believe that the woman in the car that hit me while I was riding my trike did indeed do it "unintentionally", though I feel that it was in no way unavoidable. If she had slowed down and given just a moments thought to her driving instead of whatever else she may have been thinking, this could have and I'm sure would have been avoided. As it was, she walked away without so much as a scratch while I may never get the full use of my hand/wrist back and will always have a 3.5 inch scar on my wrist and a bunch of metal inside it. I've been going through months of physical therapy and still have months more ahead of me. There was also 2 people in a second car that was hit by the same car as hit me and I know one of them was also taken to the hospital as she had a sore neck, likely whiplash.
Accidents are not fun, nor are they healthy for anyone or anything. Please think!! Avoid "accidents".