improbable
Hard to believe
Improbable means unlikely to happen or be true: It seemed improbable that anyone could survive the crash.
The word suggests something is possible but not expected—less certain than unlikely, more diplomatic than impossible.
An improbable story strains belief without being outright unbelievable: The movie featured an improbable romance between a spy and a librarian.
Unlikely to be true
- far-fetchedUnconvincingly unlikely or strained
- inconceivableBeyond mental grasp
- unthinkableToo terrible to contemplate
- preposterousCompletely contrary to reason
longshot · remote · slim · questionable · unrealistic · unbelievable · fantastical · outlandish
Causing mild shock
- unforeseenNot predicted or expected
- unanticipatedNot predicted beforehand
- unpredictableCannot be anticipated
- astonishingCausing great wonder
startling · coincidental · fluke · freak · anomalous · serendipitous · fortuitous · chance
Seldom occurring or found
- unusualNot often encountered
- exceptionalNotably above the norm
- extraordinaryBeyond what's typical
- singularOne in number
remarkable · unique · scarce · infrequent · seldom · once-in-a-lifetime · unprecedented · unheard-of
Based on conjecture
- questionableOf uncertain validity
- iffyUncertain, questionable
- indeterminateNot exactly known
- riskyInvolving possible harm
gamble · hazard · tenuous · shaky · unsettled · unpredictable · aleatory · chancy
implausible
Unlikely to be true
- far-fetchedUnconvincingly unlikely or strained
- inconceivableBeyond mental grasp
- unthinkableToo terrible to contemplate
preposterous · longshot · remote · slim · questionable · unrealistic · unbelievable · fantastical · outlandish · absurd
surprising
Causing mild shock
- unforeseenNot predicted or expected
- unanticipatedNot predicted beforehand
- unpredictableCannot be anticipated
astonishing · startling · coincidental · fluke · freak · anomalous · serendipitous · fortuitous · chance · miraculous
uncommon
Seldom occurring or found
- unusualNot often encountered
- exceptionalNotably above the norm
- extraordinaryBeyond what's typical
singular · remarkable · unique · scarce · infrequent · seldom · once-in-a-lifetime · unprecedented · unheard-of · anomaly
speculative
Based on conjecture
- questionableOf uncertain validity
- iffyUncertain, questionable
- indeterminateNot exactly known
risky · gamble · hazard · tenuous · shaky · unsettled · unpredictable · aleatory · chancy · dicey
- chancechance, luck, lottery, dice, randomness
- Unlikelyunlikely, doubtful, dubious, remote, rare
- IM- wordsimmature, immobile, immune, immerse, immoral
- long shotslong shot, longshot, long odds, dark horse, underdog
- idealisticidealist, idealistic, utopian, quixotic, dreamer
- futilityfutile, futility, in vain, pointlessness, vain
improbableprobable
Likely to occur
likely · certain · expected · inevitable · assured
improbableplausible
Appearing worthy of belief
believable · credible · convincing · realistic · reasonable