Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
praecursōrĭus, a, um, adj. [praecursor], precursory (post-Aug.): epistula, Plin. Ep. 4, 13, 2: index, Amm. 15, 1, 2 (al. procursorius).