Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
obstĭnet dicebant antiqui, quod nunc ostendit, Paul. ex Fest. p. 197 Müll.; so, iam se caelo cedens aurora obstinet suum patrem, Poët. ib. (Trag. Rel. p. 228 Rib.).