skeptical
adj.adj. doubting that something is true or useful. You feel this way when you need more proof before you can believe a claim or a promise.
adj. inclined to doubt or question claims; not easily convinced. Often followed by 'about' or 'of' to indicate the object of doubt.
I am skeptical about his promise to finish the work today.
Many scientists remain skeptical of the new study until the results can be repeated in other labs.
While the marketing team was enthusiastic about the rebranding, the board remained skeptical, demanding more data on how existing customers would perceive the change in identity.
From Latin scepticus + -al; attested earlier than skeptic. By surface analysis, skeptic + -al.
Commonly takes the prepositions 'about' or 'of'.
I am skeptical to his ideaI am skeptical of his ideaSkeptical is typically followed by 'of' or 'about', not 'to'.