IMPROBABLE

[adjective] - not likely to be true or to happen; not probable"Perhaps we haven't seen her because she's working so hard." "Sounds improbable."It's highly improbable that Norris will agree.He came up with an improbable-sounding excuse as to why they were late.An improbable-looking (= very strange) animal with a massively long nose crept out of a hole.