Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pessĭmo, āre, v. a. [pessimus], to make utterly bad, to spoil completely, to ruin (eccl. Lat.): plebem, Vulg. Ecclus. 36, 11: te ipsum pessimabis, id. ib. 38, 22.
Pass.: pessimabor, Vulg. Ecclus. 11, 26.