► unsurenot confident that you know something: If you are unsure about anything, just ask for help.
► not sure unsure: I’m not sure where she lives, but I think her house is near here.
► uncertain uncertain means the same as unsure but is more formal: She told us what happened, but she was uncertain about the details.
► unconvinced not sure that you believe something that someone wants you to believe: Mrs. Jones was unconvinced that we could paint the house all by ourselves.
► undecided not sure because you have not made a decision about something yet: I’m still undecided about who I will vote for.
► doubtful not sure whether something is true or good: Everyone says that the trip will be fun, but I’m still doubtful.
► dubious dubious means the same as doubtful but is more formal: At first I was dubious about what she told me, but then she showed me pictures.
► skeptical very doubtful about something, and not willing to believe it unless you have proof: It’s best to be skeptical of the advertisements you see on TV.