An unexpected event with negative consequences occurring without the intention of the one suffering the consequences, and (in the strict sense) not directly caused by humans.

(now nonstandard) Accidentally; by chance, unintentionally.

plural of accident

Accidentally; unintentionally; without meaning to; as the result of an event not expected, aided, or willingly planned.

Accidental; as the result of some unforeseen happening or series of events; unexpected; resulting from an event without the foresight, expectation, aid, or design of the person by whose agency it was caused; unintentional.

Accidentally; not intentionally; because of error, misfortune, or lack of caution.

A town in Maryland, United States.

(possessional) Having had an accident / That has an uneven or undulating surface

Used to imply that something was deliberate, sometimes with the connotation of dishonesty.

(astronomy, informal) A brown dwarf in Milky Way Galaxy, Local Group, Laniakea, Universe; A brown dwarf in interstellar space, thought to be the oldest brown dwarf yet discovered, and having the fastest brown dwarf galactic orbital velocity yet discovered, at the time of its discovery in 2021.