Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
in-dŭbĭto, āvi, ātum, 1, v. n., to doubt of (poet.); with dat.: viribus tuis, Verg. A. 8, 404: tuis moribus, Stat. S. 3, 5, 110.