unlikely

Not likely; improbable; not to be reasonably expected.

• It is pretty unlikely that you'll win, but I will pray that at least you do well.
• In the highly unlikely event of landing in water, lifejackets are stored under the seat.

Not holding out a prospect of success; likely to fail; unpromising.

• unlikely means

In an improbable manner.

Something or somebody considered unlikely.

• 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.
• "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."