The following definition, due to Steven Novella, pretty much sums up where we are coming from:
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.
In short skepticism is an intellectual specialty that is grounded in science and the humanities and includes any knowledge that deals with the nature of knowledge and belief, critical thinking, the foibles of the human intellect, and deception.