a. | 1. | Not probable; unlikely to be true; not to be expected under the circumstances or in the usual course of events; |
Adj. | 1. | improbable - not likely to be true or to occur or to have occurred; "legislation on the question is highly unlikely"; "an improbable event" Synonyms: unlikely |
2. | improbable - having a probability to low to inspire belief | |
3. | improbable - too improbable to admit of belief; "a tall story" |