Definition of "fortuitous"

[…] and during the ten days of their stay at Hartfield it was not to be expected—she did not herself expect—that any thing beyond occasional, fortuitous assistance could be afforded by her to the lovers.

1815 December (indicated as 1816), [Jane Austen], chapter XI, in Emma: […], volume I, London: […] [Charles Roworth and James Moyes] for John Murray

‘It is not for one, situated, through his original errors and a fortuitous combination of unpropitious events, as is the foundered Bark (if he may be allowed to assume so maritime a denomination), who now takes up the pen to address you—it is not, I repeat, for one so circumstanced, to adopt the language of compliment, or of congratulation. That he leaves to abler and to purer hands.

1849 May – 1850 November, Charles Dickens, The Personal History of David Copperfield, London: Bradbury & Evans, […], published 1850

Was it love, she wondered, or a mere fortuitous combination of happy thoughts and sensations?

1905, Edith Wharton, chapter 6, in The House of Mirth, New York, N.Y.: Charles Scribner’s Sons

And then he met John Dowsett, the great John Dowsett. The whole thing was fortuitous. This cannot be doubted.

1910 October, Jack London, chapter I, in Burning Daylight, New York, N.Y.: The Macmillan Company, part II, page 128

Admiral Kurita has no identification charts for escort carriers, and, so, assumes that the distant targets are fleet carriers. Commensurately, by scale, their escorts must either be battleships or cruisers. The Japanese forces therefore continue to load armor-piercing rounds, what will turn out to be a very fortuitous mistake for their targets for as long as it lasts.

2019 February 27, Drachinifel, 12:25 from the start, in The Battle of Samar - Odds? What are those?‎, archived from the original on 3 November 2022

England were ragged at this point but the response was full of conviction, equalising swiftly then taking control before the tiring Danes and the magnificent Schmeichel were finally overcome with Kane's fortuitous winner.

2021 July 7, Phil McNulty, “England 2-1 Denmark”, in BBC Sport‎