sceptic
(US skeptic), / ˈskeptɪk; `skɛptɪk/ n
1 person who doubts that a claim, statement, etc is true 持怀疑态度的人
The government must still convince the sceptics that its policy will work. 政府仍须使持怀疑态度的人相信其政策可行.
2 person who does not think religious teachings are true 怀疑宗教教义的人.