Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ellĕbŏrōsus (hell-), a, um, adj. [elleborus], in need of hellebore (i. e.), out of his senses: Gr. Quaeso, sanun es? Tr. Sum elleborosus. Gr. Ut ego cerritus, Plaut. Rud. 4, 3, 67.