Not likely to happen, be done, or be true; improbable
an unlikely explanation
it is unlikely that they will ever be used
the change is unlikely to affect many people
improbable: not likely to be true or to occur or to have occurred; "legislation on the question is highly unlikely"; "an improbable event"
has little chance of being the case or coming about; "an unlikely story"; "an unlikely candidate for reelection"; "a butcher is unlikely to preach vegetarianism"
improbable: having a probability too low to inspire belief
(unlikeliness) unlikelihood: the improbability of a specified outcome
Controversial. Laughable. Yet, after several years of development, their research begat the Dramatica software, which has been bestowed with some of the most incredible accolades of any creative writing tool. The Dramatica software was even granted a patent by the US Patent Office!
seeming untrue, implausible, or unlikely ( often used ironically )