Certainty and Uncertainty: English Vocabulary List

certainly happening and unlikely to change

"We need a definite answer."

"The doctor gave a definite diagnosis after running several tests and the patient finally knew what was causing his symptoms and how to treat the condition."

beyond debate or argument

"The fact is inarguable."

"The inarguable fact is that smoking causes lung cancer and there is no debate about it."

clearly true and therefore impossible to deny or question

"Her talent is undeniable."

"The evidence against the suspect was undeniable and the jury took only an hour to return a guilty verdict in the high profile murder trial."

providing clear and final evidence or proof, leaving no doubt or uncertainty

"The evidence is conclusive."

"The conclusive evidence proved that the defendant was innocent and the charges were dropped."

incapable of making mistakes or being wrong

"The system is infallible."

"While the computer is generally reliable, no system is truly infallible and occasional errors can occur."

expressing one's ideas and opinions so clearly that it leaves no room for doubt

"Her answer was unequivocal."

"The president's unequivocal support for the policy reassured voters who had been uncertain about his position."

settling an issue authoritatively and leaving no room for further doubt or debate

"The answer is definitive."

"The definitive biography of the author includes letters that were previously unavailable to researchers."

easily perceived by the mind or senses

"It is evident."

"It was evident from his red eyes that he had been crying before the meeting started."

fully established or proven beyond any doubt

"The truth is indisputable."

"The indisputable truth is that the earth orbits the sun and not the other way around."

to make sure that something will happen

"Seat belts ensure passenger safety always."

"Please check the door twice to ensure that it is locked before you leave the house for your vacation."

to determine something with certainty by careful examination or investigation

"Please ascertain the facts before speaking."

"The detective tried to ascertain the exact time of death by examining the condition of the body and the temperature of the room."

used to say that there is no doubt something is true or is the case

"She is undoubtedly talented."

"She is undoubtedly the best player on the team and everyone agrees with that opinion."

in a total or complete way

"You are absolutely right."

"You are absolutely right about that and I completely agree with everything you just said."

the probability or chance of something occurring

"The likelihood of rain is high."

"There is a high likelihood that it will rain heavily tomorrow according to the weather forecast."

a condition or situation that is unsettled, dependent on chance, or unpredictable, often causing doubt

"The uncertainty of the future made her anxious."

"The uncertainty about the election results caused stock markets to fluctuate wildly all week."

a feeling or intuition about something, often without conscious reasoning or evidence

"The detective followed his hunch and found the clue."

"He had a hunch that the missing keys were in the car even though everyone else had searched there already."

the likelihood or possibility of something becoming successful in the future

"The prospect of a promotion excited her."

"The young graduate has a bright prospect for a successful career in the technology industry."

a feeling of doubt or mistrust towards someone or something, often without concrete evidence or proof

"I have a suspicion that he took the money."

"The police had strong suspicion that the man was involved in the robbery last month."

an idea that is based on guesswork and not facts

"The theory is pure conjecture."

"His entire theory was based on pure conjecture without any solid evidence to support it."

not firmly established or decided, with the possibility of changes in the future

"We made a tentative plan."

"The two companies reached a tentative agreement after weeks of negotiation but the final contract still needs to be approved by the board of directors."

(of a person) unsure or hesitant about the credibility or goodness of something

"His claim is dubious."

"The dubious claim that drinking this juice cures cancer has been debunked by medical experts who warn consumers not to believe false advertising."

having doubts about something's truth, validity, or reliability

"I am skeptical."

"The skeptical journalist did not believe the politician's promises and she dug deeper to find evidence that would prove he was lying to the public."

asserted or claimed to be true, but not yet proven

"The alleged crime happened."

"The alleged perpetrator of the crime was questioned by the authorities but no charges were filed."

doubtful or uncertain in terms of quality, reliability, or legitimacy

"His motive is questionable."

"The questionable decision to invest in that risky company cost him most of his life savings and retirement fund."

not producing a clear result or decision

"The evidence is inconclusive."

"The results of the experiment were inconclusive so the scientists had to repeat the study with a larger sample size to obtain more reliable and valid data."

seeming believable or reasonable enough to be considered true

"Her story is plausible."

"The detective presented a plausible theory that explained all the confusing clues in the case."

uncertain or reluctant to act or speak, often due to doubt or indecision

"She is hesitant."

"The young man was hesitant to ask his boss for a raise because he was afraid of being rejected and he did not want to seem greedy or entitled."

considered true and accepted by all but not known for a fact

"The father is putative."

"The putative father of the child was asked to take a DNA test to confirm his paternity."

unable to be predicted because of changing many times

"The weather is unpredictable."

"The weather in spring is highly unpredictable so you should always carry an umbrella and a jacket with you."

likely to become a reality in the future

"A prospective buyer arrived."

"The prospective student visited the campus and met with professors before deciding which university to attend in the fall."

to propose a theory or explanation based on limited evidence

"Scientists hypothesize about the origin of life."

"Scientists hypothesize that the unusual weather patterns are caused by a combination of climate change and natural cycles."

to come to a conclusion without enough evidence

"I surmise that he is lying."

"From the muddy footprints on the carpet the detective could surmise that the intruder had entered through the back door."

used to suggest that something is assumed to be true, often with a hint of doubt

"Supposedly he is the best doctor."

"Supposedly he is the best doctor in the city but I have heard some negative reviews from his former patients."

the state of feeling confident, certain, or self-assured about one's abilities, decisions, or actions

"Have assurance in yourself."

"She spoke with great assurance, confident that her well-researched proposal would be accepted."

certainly happening and unlikely to change

"The answer is definite."

"The answer is definite and there is no ambiguity or uncertainty about what we need to do."

used for strong emphasis or exaggeration

"It was absolutely perfect."

"The surprise party was absolutely wonderful, exceeding all of our expectations for the evening."

a hypothetical sequence of events or a plausible situation that could unfold

"Imagine this scenario."

"The contingency plan outlined a detailed scenario for responding to potential cybersecurity threats."

unverified talk or rumor circulated informally

"It is just hearsay."

"Without concrete evidence, the accusation remained mere hearsay, unsubstantiated by any factual basis."

a lingering uncertainty or hesitation that prevents full acceptance or commitment to something

"I have a reservation about this."

"Despite the initial success, the committee harbored a reservation regarding the long-term sustainability of the project."

hesitant, timid, and not having enough confidence

"He was tentative about the plan."

"Her tentative steps into public speaking gradually gave way to confident pronouncements."

(of a person) unsure or hesitant about the credibility or goodness of something

"The claim is dubious."

"The claim is dubious and there is no evidence to support what he is saying."

having the possibility to develop or be developed into something particular in the future

"He has potential."

"The potential benefits of the new treatment outweigh the risks and the doctors recommended that the patient try it."

to form a theory or opinion about a subject without knowing all the facts

"Analysts speculate about the company's future."

"Financial analysts often speculate about the company's future performance based on limited information available to the public."

to express various scenarios about something without necessarily basing it on evidence or facts

"They theorize about aliens."

"The archaeologist theorized that the ancient structure was actually an astronomical observatory rather than a temple as previously believed."