Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
intellectŭālis, e, adj. [2. intellectus], of or relating to the understanding, intellectual, App. Dogm. Plat. p. 3, 1; Aug. de Gen. ad Lit. 12, 7.
Adv.: intellectŭā-lĭter, intellectually, Claud. Mam. Stat. An. 2, 5.