means A questioning attitude that withholds belief until claims are backed by evidence or sound reasoning.

from From Greek 'skeptikos,' meaning 'thoughtful' or 'inquiring,' built on 'skeptesthai,' to look carefully or examine. It named the Skeptics, ancient Greek philosophers who made a discipline of doubting whether anything could be known for certain. The word reached English in the 16th–17th centuries by way of Latin and French, carrying that old habit of squinting hard at every claim before nodding along.