Sceptical means doubting whether a claim is true. Not refusing to believe — waiting to be convinced.
It takes about or of. The word describes a stance rather than a conclusion, which is why science treats it as a virtue and salespeople treat it as an obstacle. British English spells it with a c and American English with a k. The noun is scepticism and the person is a sceptic. It is worth keeping apart from cynical, which assumes bad motives rather than merely doubting evidence.
1adjectivescepticalDoubtful about whether something is true or worthwhile.
“She remained sceptical about the whole scheme.”
Also accepted in games: skeptical
by surface analysis, sceptic + -al.
Etymology from Wiktionary, CC BY-SA