too improbable to admit of belief

not likely to be true or to occur or to have occurred

Not promising; likely to fail, Not likely; improbable; not to be reasonably expected, Not likely; improbable; not to be reasonably expected; as, an unlikely event; the thing you mention is very unlikely. Not holding out a prospect of success; likely to fail; unpromising; as, unlikely means, adverb_ In an unlikely manner, In an improbable manner, noun_ Something or somebody considered unlikely

Perhaps, In a possible manner; by possible means; especially, by extreme, remote, or improbable intervention, change, or exercise of power; by a chance; perhaps, to a degree possible of achievement or by possible means