Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
illūmĭnātor (inl-), ōris, m. [illumino], an enlightener (eccl. Lat.), trop.: religionis Christus, Tert. Adv. Marc. 4, 17 fin.: noster Deus, Lact. 6, 18.