Dubiously

"Will you let me make the tea?" said Anne dubiously.

They had perpetuated a dubiously holy union of Church and State that had refused for centuries to hear the cry of the poor and the oppressed.

But, this information is relegated to a footnote, and no examples of dubiously English words are provided.

She looked dubiously up the steep path to the vastness of dark wood on either side. “How far is it up to the top?”