If you are sceptical about something, you have doubts about it.
例句
Other archaeologists are sceptical about his findings.其他考古學家對他的發現表示懷疑。...scientists who are sceptical of global warming and its alleged consequences...對全球變暖和各種斷言的后果持懷疑態度的科學家
英漢詞典釋義
adj.
不肯相信的; 常懷疑的
I am rather sceptical about their professed sympathy for the poor.他們聲稱同情窮人, 我對此相當懷疑。
英英詞典釋義
Adjective
1. marked by or given to doubt;
"a skeptical attitude""a skeptical listener"
2. denying or questioning the tenets of especially a religion;