Adoption of a neutral stance in regard to issues which have not been conclusively resolved.
A skeptic is someone who, in front of claims or theories for which the available evidence is not enough to reach a definitive conclusion either in favor or against, does not take a position, but waits until more proof is collected. As such, a real skeptic always welcomes any attempt at research and investigation, including (when not especially) in fringe or controversial topics that few dare to approach.
Skepticism is a necessary precondition of science, since research and falsification are fundamental parts of the scientific method. However, skepticism by itself can never act as a substitute for science.
In neo-obscurantist language, "skepticism" refers to the dogmatic rejection of any claim or theory that goes contrary to academically accepted theories or common everyday experience, often in spite of any existing favorable evidence.
A "skeptic" in mediatic/social discourse is someone who, instead of suspending judgement and awaiting for more evidence, immediately issues a negative judgement *before* any serious attempt at obtaining evidence can be conducted, ignores or lazily dismisses the already available evidence, and sometimes even actively tries to prevent any further investigation on the subject.
The actual name for this kind of fake skepticism is "pseudo-skepticism", and is actually a camouflaged form of religious dogmatism.