Definition of "unlikely"

Now, I still think that for this box of matches to have escaped the wear of time for immemorial years was a strange, and for me, a most fortunate thing. Yet oddly enough I found here a far more unlikely substance, and that was camphor.

1895 May 7, H[erbert] G[eorge] Wells, chapter X, in The Time Machine: An Invention, New York, N.Y.: Henry Holt and Company

The Saturday evening Cardiff-West Wales mail train is still steam-worked, but a most unlikely locomotive used on May 23 was Stanier Class 5 4-6-0 No. 45250 (5A); it returned on May 25 with a train of steel billets.

1964 July, “Motive Power Miscellany: Western Region”, in Modern Railways, page 70

The molecular ion candidates are divided by the testing phase into three categories: rejects, unlikelies, and probables. Differences between each candidate and the prominent peaks in the spectrum are computed.

1980, Robert K. Lindsay, Applications of artificial intelligence for organic chemistry

"Here is my every possible phone number, plus a few unlikelies. And I've also put down the numbers of Karin and Wade, in case you've lost them. Karin can come anytime; Wade, up until six in the morning."

1996, Laurie R. King, To Play the Fool

Then the most unlikely of unlikelies happened. We got another phone call. Another woman wanted to give us a baby—a boy, born just that morning. We walked into a hospital, and he was placed into my arms.

2001, Jack Canfield, Mark Victor Hansen, Marci Shimoff, Chicken soup for the mother's soul 2, page 166