Improbable
WordNet
adjective
(1) Too improbable to admit of belief
"A tall story"
(2) Not likely to be true or to occur or to have occurred
"Legislation on the question is highly unlikely"
"An improbable event"
(3) Having a probability too low to inspire belief
WiktionaryText
Adjective
improbable
- Not likely to be true.
- It's highly improbable that aliens abducted you.
- Not likely to happen.
- Due to the loss of power, it is improbable that we will begin on time.