Someone who does not believe in something unless given reasonable evidence supporting an issue. Initially disbelieving but open-minded.Now here are some modern definitions:
- A person who questions or doubts something (such as a claim or statement) : a person who often questions or doubts things. Merriam-Webster.
- A skeptic is one who prefers beliefs and conclusions that are reliable and valid to ones that are comforting or convenient, and therefore rigorously and openly applies the methods of science and reason to all empirical claims, especially their own. A skeptic provisionally proportions acceptance of any claim to valid logic and a fair and thorough assessment of available evidence, and studies the pitfalls of human reason and the mechanisms of deception so as to avoid being deceived by others or themselves. Skepticism values method over any particular conclusion. Source.
- One inclined to skepticism in religious matters. 2.
In general, it's a good idea to question things, try to get confirmation. Don't be so open-minded your brains fall out, but don't be close-minded that no good ideas seep in. I.e. Question, but be reasonable.