What does uncertain mean?
Uncertain describes a lack of firm knowledge, confidence, or predictability. People are uncertain when they cannot make a confident decision, while an outcome, future, or situation is uncertain when it cannot be reliably predicted or clearly defined. The word is common in everyday speech and formal writing and can describe either a person's state of mind or the instability of a situation. For example, someone may be uncertain about a career choice, or a company may face an uncertain market. Compared with “unsure,” which often focuses more directly on a person's feelings, “uncertain” has a broader range of uses and can apply to evidence, conclusions, futures, and outcomes. It is also useful in discussions of science, politics, economics, and personal judgment because it distinguishes what is not yet known from what has been positively disproved. The related noun “uncertainty” names the condition itself.
adjectiveNot knowing or sure about something; unable to make a confident choice or prediction.
- Unable to determine something with confidence or make a firm decision.
- Not predictable, settled, or clearly defined.
- Hesitant or lacking confidence in one's knowledge, judgment, or intentions.
"The outcome remains uncertain, so the organizers have prepared for several possible scenarios."
"Researchers remain uncertain about the causes of the decline."
"An uncertain economy can make even sound financial decisions difficult."
Uncertain comes from the Latin incertus, literally “not certain”: the word carries the idea of certainty inside its own history.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does uncertain come from?
Uncertain entered English in the early 17th century from Latin incertus, formed from the prefix in- and certus, meaning “certain.” Latin incertus therefore originally conveyed the idea of “not certain” or “unsettled.” The same root appears in related English words such as certain, ascertain, certify, and certainty.
Related word forms
How uncertain is actually used
The adjective is neutral in register and common in both spoken and written English. In formal prose, it often suggests insufficient evidence or an unresolved question, while in descriptions of people it can convey hesitation or indecision.
Easily confused with uncertain
To assure someone is to give them confidence, whereas to be uncertain is to lack confidence or certainty.